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