sparse coding under occlusions: individual tree ... · kvk 1 + k p n i=1 v ie i fk 2 2 o ......
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Sparse Coding under Occlusions: Individual TreeSegmentation in Remote Sensing
Xiaohao Cai
Department of Applied Mathematics and Theoretical Physics (DAMTP)University of Cambridge
withD. Coomes, J. Lee, J. Lellmann, C.-B. Schonlieb
Challenges in Dynamic Imaging Data
June 09–11, 2015
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Object detection
Synthetic Synthetic Synthetic
Coin Apple Tree CHM of LiDAR
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Sparse coding model - original
minv∈RN
{λ‖v‖1 + ‖
∑Ni=1 viei − f ‖22
}
I Given image f ∈ RM1×M2
I Regularisation parameterλ > 0
I Library E = {e1, . . . , eN},where ei ∈ RM1×M2
I Coefficient vectorv = (v1, . . . , vN)> ∈ RN
I ‖ · ‖1 – enforces sparserepresentation of v
ei ∈ Evi 6= 0vi = 0
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Sparse coding model - extended
minv∈RN
{λ‖v‖1 + ‖
∑Ni=1 viei − f ‖22
}given image
�
@@Rextended
I Fail under occlusion case
I No parallelism
∑Ni=1 viei
HHY
vHHY
I Work under occlusion case
I Parallelism
new∑N
i=1 vieiHHY
new vHHY
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Preliminary results
Given apple image Our result Our v - object position
Given tree CHM Our result Our v - object position
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Conclusions
Aim
I Tree segmentation fromremote sensing data – largedata
I Sparse coding underocclusions method
I Parallel computation
Challenging aspects
I Proper library (E ) selection
I Robust and goodperformance
I Automatic software toolbox
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THANK YOU!