Vectorial Distortion For Performance EvaluationCurrent investigations ….
Mathieu Delalandre and Ernest Valveny
Meeting of Document Analysis Group
Computer Vision CenterBarcelona, Spain
Thursday 21th February 2007
IntroductionPerformance Evaluation of Graphics Recognition Systems
Binary Noise
Groundtruthing
Synthetic Document
Vectorial Distortion
IntroductionVectorial Distortion
You see 5 You have 9
Noise related to layer model and viewer
Noise related to user
Noise related to image processing
Document Understanding
Computer Aided Design
On-line sketch
How to improve them ?
Existing methods produce
no “real” distortions
Vectorial noise is liked to a produce
model
IntroductionHand-Sketch Distortion
True-lifeDatabase
Characterisation Process
“set of criteria”
System proposal
Symbols/Class
020406080100120140160180200
simbol1n
simbol4n
simbol7n
simbol10n
simbol16n
simbol21n
simbol24n
simbol27n
simbol30n
simbol33n
simbol38n
simbol41n
simbol44n
simbol47n
simbol50n
Classes
Sy
mb
ol
How to define a system allowing to generate “realistic”
distortion
43 classes, 5370 symbols
Main features of hand-sketches
CVC Database
The purpose is to copy realistic
noiseTo do a
characterisation process
Characterisationin progress …
sketch proportions are few respected”
dx
dy
Streching Distribution
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
5
streching rate (%)
sym
bo
l (%
)
x
y
dd
s
ms
ms
ss
sss
symbol (s) and model (m)
straight lines look like curves and orientations are few respected
Orientation Radiogram
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
Orientation (0-PI)
Leng
th R
ate
(0-1
)1
0 0
i
n
j
ojiilo
Characterisationin progress …
relative positioning of strokes arerespected but not junctions
Characterisationin progress …
users use stroke sequences
First SystemCurrent proposal
Curve distortion
Line shockScale distortion
12 3
45
67
{21,13,34}
{42}{76,65,5
4}
Line graph
Stroke sequenceModel
Previous works
First SystemCurve Distortion
Barraud’05 “Bezier approximation”
(1) Line split to polyline using a regular gap(2) Circle projection of points using a parameter
Obtained points correspond to control point Pi of Bezier curve
)()(,
0
ttP BP ni
n
ii
)1()(, ttCB
inii
nnit
Bezier curve
Bernstein polynomial
First SystemCurve Distortion
Barraud’05 “clipping effect”
(1) Split the curve according dominant control point(2) Delete a fixed rate of smallest curves
First SystemCurve Distortion
Proposed improvements
(1) To formalize the point selection as a sampling process
(2) To perform a random selection of points
(3) To use a Gaussian projection of points
fs=0.08 fs=0.1
First SystemLine Shock
ICDAR’07
variance: 0.001 0.005 0.010
scaling
rotation
moving
vvf s 10
vdvf xmx
vvf s 110
vvfr
vdvf ymy v0
x
s [0,1]
y
vmax
(b)
v x
es0
2
12
2
1
(a)
2
vzerfs
l
n
nn
nn
z
0
12
)12(!
)1(2
2.02
52
12
12
Questions and Discussions
