radiation laboratory quantifying the effects of wind on polarimetric sar & insar tree height...
TRANSCRIPT
Radiation Laboratory
Quantifying the Effects of Wind on polarimetric SAR amp InSAR
Tree height estimation
Michael L BensonDr Leland E Pierce
Prof Kamal Sarabandi
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Motivationbull InSAR is often used over forested areas to obtain information
on forest structuresbull Repeat-pass InSAR over forests suffers from poor coherence
due to changes in a forests physical attributes (exact position motion of branches leaves etc) and moisture which affects the dielectric constant of the scatterers
bull Is there a way to obtain high-coherence repeat-pass InSAR data using models of these effects
bull Could we then produce reliable high-quality forest structure estimates including canopy height
bull This research presents a detailed model of the effects of wind on SAR image formation coherence and the associated effect on tree height retrieval through the scattering phase center
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
bull Use our existing Lindenmayer system based fractal tree generator [Lin + Sarabandi IGRS 1999]
bull Trees defined by a DNA file
bullConsists of basic parameters such as leaf radius leaf thickness and maximum branch angle
bullDifferent DNA for each species
bullDNA is iterated a set number of times to form a complex semi-random tree realization
bullDNA sub-string re-writing rules are used to generate realistic branching structures with needles leaves
bull Current study uses a deciduous red maple stand only
Tree Generation
Radiation Laboratory
bull Generate both coniferous and deciduous trees including
bull Red Maple
bull Red Oak
bull Red Pine
bull Sugar Maple
bull White Ash
bull White Pine
bull White Spruce
bull DNA files only specify tree structure InSAR parameters are specified elsewhere
Tree Generation (2)
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation LaboratoryModelling Wind
Branchesbull Need to know
bull Mechanical Parameters
bull Length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Parent amp Children
bull Youngrsquos Modulus E
bull Need to Find
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Motivationbull InSAR is often used over forested areas to obtain information
on forest structuresbull Repeat-pass InSAR over forests suffers from poor coherence
due to changes in a forests physical attributes (exact position motion of branches leaves etc) and moisture which affects the dielectric constant of the scatterers
bull Is there a way to obtain high-coherence repeat-pass InSAR data using models of these effects
bull Could we then produce reliable high-quality forest structure estimates including canopy height
bull This research presents a detailed model of the effects of wind on SAR image formation coherence and the associated effect on tree height retrieval through the scattering phase center
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
bull Use our existing Lindenmayer system based fractal tree generator [Lin + Sarabandi IGRS 1999]
bull Trees defined by a DNA file
bullConsists of basic parameters such as leaf radius leaf thickness and maximum branch angle
bullDifferent DNA for each species
bullDNA is iterated a set number of times to form a complex semi-random tree realization
bullDNA sub-string re-writing rules are used to generate realistic branching structures with needles leaves
bull Current study uses a deciduous red maple stand only
Tree Generation
Radiation Laboratory
bull Generate both coniferous and deciduous trees including
bull Red Maple
bull Red Oak
bull Red Pine
bull Sugar Maple
bull White Ash
bull White Pine
bull White Spruce
bull DNA files only specify tree structure InSAR parameters are specified elsewhere
Tree Generation (2)
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation LaboratoryModelling Wind
Branchesbull Need to know
bull Mechanical Parameters
bull Length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Parent amp Children
bull Youngrsquos Modulus E
bull Need to Find
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Motivationbull InSAR is often used over forested areas to obtain information
on forest structuresbull Repeat-pass InSAR over forests suffers from poor coherence
due to changes in a forests physical attributes (exact position motion of branches leaves etc) and moisture which affects the dielectric constant of the scatterers
bull Is there a way to obtain high-coherence repeat-pass InSAR data using models of these effects
bull Could we then produce reliable high-quality forest structure estimates including canopy height
bull This research presents a detailed model of the effects of wind on SAR image formation coherence and the associated effect on tree height retrieval through the scattering phase center
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
bull Use our existing Lindenmayer system based fractal tree generator [Lin + Sarabandi IGRS 1999]
bull Trees defined by a DNA file
bullConsists of basic parameters such as leaf radius leaf thickness and maximum branch angle
bullDifferent DNA for each species
bullDNA is iterated a set number of times to form a complex semi-random tree realization
bullDNA sub-string re-writing rules are used to generate realistic branching structures with needles leaves
bull Current study uses a deciduous red maple stand only
Tree Generation
Radiation Laboratory
bull Generate both coniferous and deciduous trees including
bull Red Maple
bull Red Oak
bull Red Pine
bull Sugar Maple
bull White Ash
bull White Pine
bull White Spruce
bull DNA files only specify tree structure InSAR parameters are specified elsewhere
Tree Generation (2)
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation LaboratoryModelling Wind
Branchesbull Need to know
bull Mechanical Parameters
bull Length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Parent amp Children
bull Youngrsquos Modulus E
bull Need to Find
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
bull Use our existing Lindenmayer system based fractal tree generator [Lin + Sarabandi IGRS 1999]
bull Trees defined by a DNA file
bullConsists of basic parameters such as leaf radius leaf thickness and maximum branch angle
bullDifferent DNA for each species
bullDNA is iterated a set number of times to form a complex semi-random tree realization
bullDNA sub-string re-writing rules are used to generate realistic branching structures with needles leaves
bull Current study uses a deciduous red maple stand only
Tree Generation
Radiation Laboratory
bull Generate both coniferous and deciduous trees including
bull Red Maple
bull Red Oak
bull Red Pine
bull Sugar Maple
bull White Ash
bull White Pine
bull White Spruce
bull DNA files only specify tree structure InSAR parameters are specified elsewhere
Tree Generation (2)
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation LaboratoryModelling Wind
Branchesbull Need to know
bull Mechanical Parameters
bull Length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Parent amp Children
bull Youngrsquos Modulus E
bull Need to Find
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
bull Use our existing Lindenmayer system based fractal tree generator [Lin + Sarabandi IGRS 1999]
bull Trees defined by a DNA file
bullConsists of basic parameters such as leaf radius leaf thickness and maximum branch angle
bullDifferent DNA for each species
bullDNA is iterated a set number of times to form a complex semi-random tree realization
bullDNA sub-string re-writing rules are used to generate realistic branching structures with needles leaves
bull Current study uses a deciduous red maple stand only
Tree Generation
Radiation Laboratory
bull Generate both coniferous and deciduous trees including
bull Red Maple
bull Red Oak
bull Red Pine
bull Sugar Maple
bull White Ash
bull White Pine
bull White Spruce
bull DNA files only specify tree structure InSAR parameters are specified elsewhere
Tree Generation (2)
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation LaboratoryModelling Wind
Branchesbull Need to know
bull Mechanical Parameters
bull Length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Parent amp Children
bull Youngrsquos Modulus E
bull Need to Find
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
bull Generate both coniferous and deciduous trees including
bull Red Maple
bull Red Oak
bull Red Pine
bull Sugar Maple
bull White Ash
bull White Pine
bull White Spruce
bull DNA files only specify tree structure InSAR parameters are specified elsewhere
Tree Generation (2)
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation LaboratoryModelling Wind
Branchesbull Need to know
bull Mechanical Parameters
bull Length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Parent amp Children
bull Youngrsquos Modulus E
bull Need to Find
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation LaboratoryModelling Wind
Branchesbull Need to know
bull Mechanical Parameters
bull Length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Parent amp Children
bull Youngrsquos Modulus E
bull Need to Find
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation LaboratoryModelling Wind
Branchesbull Need to know
bull Mechanical Parameters
bull Length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Parent amp Children
bull Youngrsquos Modulus E
bull Need to Find
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation LaboratoryModelling Wind
Stems amp Leavesbull Need to know
bull Mechanical Parameters
bull Stem length l
bull Center (x y z)
bull Orientation (ΘΦ)
bull Family (branch stem leaf)
bull Youngrsquos Modulus E
bull Leaf thickness t
bull Need to Find for each stem-leaf pair
bull Moment of Inertia I
bull Resonant Frequency fr
bull Deflection angle α
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Modelling Winda single branch
m
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Modelling Windmultiple branches
W
Θ = 80deg
Θ = 45deg
Θ = 90deg
z
y
x
WaN = 0889
WaN = 05
WaN = 10
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Modeling Windbull A steady wind force on the branch causes a vibration with
frequency bull Moment of Inertia I is determined by the mass distribution in
the branch as well as the mass of branches attached to its end
bull Youngs Modulus E is a measure of the stiffness of the
branch measurements of E for different species are availablebull Tree motion composes each branch motion using movement
of lower branches to alter locations of upper branches
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Modelling Wind Branch Motionbull A steady wind force on the branch causes a vibration with
frequency
bull How far should each branch movebull Depends on the wind velocity and the branchrsquos physical
parametersbull Assuming T = 25 C and average moisture content in each
branch calculate the maximum deflection for each branch as
bull Under SHM approximation branch will be directly moved along the direction of the wind field a maximum of frac12 max in any direction However branches may move more than frac12 max relative to their original (rest) position as a result of their parentsrsquo motion
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Modelling Wind Branch Motion (2)bull Where does Φmax come from
bull Pressure due to wind is [httpwwwvent-axiacomknowledgehandbooksection1windflowasp ]
bull Branch surface area (SA) presented to wind is ~
bull Maximum deflection for a cantilever is defined as [httpdarkwinguoregonedu~structcourseware461461_lectures461_lecture40461_lecture40html ]
bull Use of simple trigonometric relationships yield Φmax as
ymax
Φmax
L L
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation LaboratoryModelling Wind Constant
Breeze Movie
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
InSAR Simulator (1)bull Divide stand into several horizontal slabsbull In each slab estimate the mean field using Foldys
approximation [Lin + Sarabandi IGARSS 1996]bull Also estimate attenuation through each slabbull For each branch or leaf in the tree calculate the backscattered
field as Escat = Einc Seiɸ where S is the scattering matrix of the object and ɸ is the relative phase of the scattering due to the relative position of this object in the tree
bull The scattering matrix is estimated using four (4) scattering mechanismsndash Direct Scattering St ndash Ground-Object scattering Sgt
ndash Object-Ground scattering Stg
ndash Ground-Object-Ground Sgtg
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
InSAR Simulator (2)bull Use Δk Approach [Sarabandi TGRS 1997]bull Approximate InSAR baseline with a small change in frequency
bull Measured phase can be calculated as
bull For each polarization calculate a scattering phase center as
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Combined InSAR and Windbull Produced 5 instances of a single red maple without the influence of
wind and placed them in a 625 m2 regionbull Applied wind to these trees and saved all geometries for each time
step in the simulationndash Δt = 002s total time = 1s
bull Use InSAR simulator to produce a single-look complex (SLC) image of a one-pixel forest stand for each geometry at each time step This includes the no-wind case
bull Now can produce a coherence estimate between pairs of SLC images
Where u1 is the no-wind tree and u2 is one sample from a wind-blown tree sequence
bull Can plot this as a function of time
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Forming a SAR Imagebull A SAR image formed with multiple looks in practice will be
collected over a period of time often under 1 secondbull Wind Speeds below vary from a strong breeze to a sustained
hurricane force wind
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Overview
bull Motivationbull Tree Modelbull Wind Modelbull InSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Future Work
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Coherence and Height Estimationbull This Coherence measurement can also be thought of as a
measure of similarity between two SAR images taken at different times The only difference between the two images is a wind induced motion
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Coherence and Height Estimationbull At L-band the principal contributor to the VV-polarization from
the target will be the tree trunks As the wind height increases the mean scattering phase center height decreases at a nearly consistent rate
mean SPCbull Strong Breeze 39777mbull Stronger Breeze 35758mbull Storm Gust 29520m
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Coherence and Height Estimationbull The physical description of the windrsquos effect on higher frequency
(C-band) tree height estimate is not as straight forward as the L-band VV case
bull We have observed that the co-polarized mean SPC increases with an increasing wind force while the mean cross-polarized SPC decreases
Mean Scattering Phase Center Height [m]
Strong Breeze Storm Gust
VV C-Band 65587 69315
HH C-Band 27823 28971
VH C-Band 87781 72317
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Overview
bull Introductionbull Tree Modelbull Wind Modelbull ifSAR Simulatorbull SAR Image Coherencebull InSAR Height Estimatebull Conclusions and Future Work
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Conclusions and Future Workbull Developed a realistic wind model for trees including branches stems
leaves and needles and demonstrated it on a red maple stand
bull Applied SAR and InSAR model to the stand with and without wind
bull Calculated coherence between wind no-wind cases to simulate repeat-pass InSAR
bull Showed poor coherence for both L-band and C-bandndash This is only due to the movement of the branches and leaves
bull Showed wind effect on IfSAR Tree Height estimation
bull Future Workndash Different moisture conditions in branches and leavesndash Large database generation
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Questions
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Extra Slides
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Coherence due to Windinc angle = 436deg
bull L-band coherence drops below 07 at 239s 101sbull C-band coherence drops below 07 at 16s 07sbull C-band has significantly more scattering from the trees upper
branches than does L-band and so their movement will create greater decorrelation at C-band than L-band
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0
Radiation Laboratory
Windrsquos effectσ0 comparison
bull At both L and C bands variations in σ0 are minimalbull σ0 is relatively unaffected by wind motion
L-Band C-Band
σ0