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Searching by shape in heterogeneous Searching by shape in heterogeneous databases databases
IntroductionIntroduction AlgorithmsAlgorithms MethodologyMethodology ExperimentsExperiments Conclusions and future worksConclusions and future works
Searching criteriaSearching criteria
ColourColour
TextureTexture
Spatial relationshipsSpatial relationships
ShapeShape
Searching by shapeSearching by shape
Features:Features:
Rotation invariantRotation invariant
Translation invariantTranslation invariant
Scaling invariantScaling invariant
FastFast
Not adaptiveNot adaptive
First algorithmFirst algorithm
Features:Features:
It works on contoursIt works on contours
It is scalarIt is scalar
No feedbackNo feedback
Required invariants assuredRequired invariants assured
ParametersParameters
C
d1
d2
Distanze ordinate
Ampiezza
d1
d2
f(x)= ax3+ bx2+ cx+d
ConsiderationsConsiderations
Advantages:
Good result in a few cases
Very fast (only 4 parameters)
Rotation transaltion scaling invariance
Disadvantages:
Sensitivity to little local variations
Symmetric shapes make the algorithm collapse
Second algorithmSecond algorithm
C
0.25
0.5
0.75
1
0°
120°
60°
180°
240°
300°
1 ) Mass center is computed
2) Inertial axisi are computed
3) 4 annulus are plotted
4) 6 sector are plotted
Matrix generationMatrix generation
C
0.25
0.5
0.75
1
0°
120°
60°
180°
240°
300°
0°-60°
60°-120°
120°-180°
180°-240°
240°-300°
300°-360°
00.25
0.250.5
0.50.75
0.751
d1
0°-60°
60°-120°
120°-180°
180°-240°
240°-300°
300°-360°
00.25
0.250.5
0.50.75
0.751
d1
Matrix comparisonMatrix comparison
Query matrix Matrix image 2
Matrix image N
Matrix image 11
Images are
ranked
according to
similarity
PerformancePerformance
Precision & RecallPrecision & Recall
ProblemProblem
When an element is relevant?When an element is relevant?
We need a classification in the databaseWe need a classification in the database
The databaseThe database
Database of 4553 images by Corel DrawDatabase of 4553 images by Corel Draw
Heterogeneous images for size, subject and colourHeterogeneous images for size, subject and colour
We define 22 categories of different cardinality We define 22 categories of different cardinality
(from 54 to 400)(from 54 to 400)
Choice of categoriesChoice of categories
A trade off between:A trade off between:
Subdivision basing upon the shape of the objectSubdivision basing upon the shape of the object
I. e. simboli poligonali =Polygonal simbolsI. e. simboli poligonali =Polygonal simbols
Subdivision basing upon the semantic meaning of teh Subdivision basing upon the semantic meaning of teh
objects (i.e. flying objects)objects (i.e. flying objects)
ExperimentsExperiments
Different level of resolution (wavelets)Different level of resolution (wavelets)
20 query for each category and each resolution level20 query for each category and each resolution level
There is not a priviledged level There is not a priviledged level
of resolution for all classesof resolution for all classes
ExperimentsExperimentsSimboli Tondi
Cardinalità Precision5
Precision10
Precision15
Precision20
Precision25
Ideale 374 1 1 1 1 1
Imm. Base 374 0,644 0,595 0,523 0,533 0,541
Livello 1 374 0,660 0,639 0,602 0,557 0,529
Livello 2 374 0,540 0,441 0,432 0,454 0,455
Livello 3 374 0,550 0,426 0,434 0,426 0,424
Simboli a Scudo
Cardinalità Precision5
Precision10
Precision15
Precision20
Precision25
Ideale 301 1 1 1 1 1
Imm. Base 301 0,544 0,464 0,421 0,398 0,370
Livello 1 301 0,608 0,488 0,453 0,422 0,403
Livello 2 301 0,688 0,592 0,533 0,486 0,459
Livello 3 301 0,600 0,484 0,456 0,416 0,386
ExperimentsExperiments
Analysis of the results for each categoryAnalysis of the results for each category
More 20 queries for each category at the best More 20 queries for each category at the best resolutionresolution
Precision > 60%Precision > 60%
ExperimentsExperimentsCategorie Cardinalità
Precision5
Precision10
Precision15
Precision20
Precision25
A. Reali 300 0,330 0,270 0,213 0,200 0,180
A. Stilizzati 131 0,268 0,194 0,152 0,120 0,110
Automezzi 54 0,320 0,205 0,157 0,130 0,116
Case 81 0,240 0,153 0,110 0,093 0,090
Composizioni 247 0,330 0,265 0,223 0,190 0,176
Dinosauri 95 0,470 0,360 0,300 0,268 0,244
F. Atipiche 400 0,360 0,260 0,223 0,190 0,176
Frasi 101 0,240 0,145 0,123 0,103 0,094
Insetti 132 0,310 0,190 0,157 0,140 0,128
O. Allungati 145 0,660 0,520 0,427 0,380 0,360
O. Poligonali 391 0,490 0,355 0,294 0,273 0,242
O. Curvilinei 197 0,280 0,160 0,140 0,113 0,098
O. Volanti 332 0,490 0,335 0,294 0,273 0,242
Pers. Reali 200 0,460 0,330 0,287 0,283 0,276
Pers. Stilizzate 161 0,408 0,240 0,205 0,222 0,195
Pesci 164 0,376 0,248 0,207 0,188 0,178
Scene 123 0,240 0,133 0,107 0,095 0,088
S. Poligonali 361 0,454 0,304 0,276 0,238 0,220
S. Tondi 374 0,660 0,639 0,602 0,557 0,529
S. a Scudo 301 0,688 0,592 0,533 0,486 0,459
Uccelli 208 0,333 0,200 0,156 0,139 0,120
Visi 55 0,260 0,145 0,127 0,110 0,096
ExperimentsExperiments
Query:
1° 2° 3° 4° 5°
6° 7° 8° 9° 10°
Distanze
1°- 0
2°- 0,0803
3°- 0,0896
4°- 0,0909
5°- 0,1006
6°- 0,1039
7°- 0,1041
8°- 0,1070
9°- 0,1087
10°- 0,1117
ExperimentsExperiments
1° 2° 3° 4° 5°
6° 7° 8° 9° 10°
Query:
Distanze
1°- 0
2°- 0,0483
3°- 0,0710
4°- 0,0813
5°- 0,0871
6°- 0,0922
7°- 0,0927
8°- 0,0936
9°- 0,0938
10°- 0,0952
ExperimentsExperiments
1° 2° 3° 4° 5°
6° 7° 8° 9° 10°
Query:
Distanze
1°- 0
2°- 0,1289
3°- 0,1433
4°- 0,1506
5°- 0,1520
6°- 0,1545
7°- 0,1546
8°- 0,1578
9°- 0,1585
10°- 0,1594
DistancesDistances
0 50 100 150 200 250 300 350 400 450 5000
0.05
0.1
0.15
0.2
0.25
Number of images
Dis
tan
ces
ConclusionsConclusions
The method is:The method is:
FastFast
Acceptable precision for some classesAcceptable precision for some classes
Future worksFuture works
Upgrade of thealgorithmUpgrade of thealgorithm
Fusion with colour or texture methodsFusion with colour or texture methods