FRE 2645 GREC 2003 : 31 July 2003 Local Structural Analysis: a Primer Mathieu Delalandre¹, Eric Trupin¹, Jean-Marc Ogier² ¹PSI Laboratory, Rouen University, France ²L3I Laboratory, La Rochelle University, France

GREC 2003 : 31 July 2003Diapo 2 Plan  Introduction  General Decomposition  Method Comparison  Method Combination  Conclusion

GREC 2003 : 31 July 2003Diapo 3 Plan  Introduction  General Decomposition  Method Comparison  Method Combination  Conclusion

GREC 2003 : 31 July 2003Diapo 4 Introduction  shape recognition process  statistical analysis and recognition (Jain 2000)  structural analysis and recognition (Tombre 1996) feature extraction or ‘analysis’ (Loncarnic 1998) recognition A B D C

GREC 2003 : 31 July 2003Diapo 5 Introduction  structural recognition  graph-matching approach (Hancock 2002)  grammar approach (Blostein 1995)  structural analysis local global

GREC 2003 : 31 July 2003Diapo 6 Plan  Introduction  General Decomposition  Method Comparison  Method Combination  Conclusion

GREC 2003 : 31 July 2003Diapo 7 General Decomposition  four steps: object graph extraction mathematical approximation A B D C high level object construction object graph correction A B D C A B D C

GREC 2003 : 31 July 2003Diapo 8 General Decomposition  step 1, object graph extraction (1) skeletonisationcontouring meshesregion runtracking segmented object

GREC 2003 : 31 July 2003Diapo 9 General Decomposition  step 1, object graph extraction (2)  skeletonisation based methods, two steps:  skeletonisation (Lam 1995)  skeleton graph extraction (Tombre 1999)(Lau 2002)  contouring based methods  morphological based methods (Hasan 2000)  following based methods (Ablameyko & Pridmore 2000)  tracking based methods, two tracking types:  line tracking (Song 2002)  junction tracking (Ogier 1992) skeletonisation contouring tracking

GREC 2003 : 31 July 2003Diapo 10 General Decomposition  step 1, object graph extraction (3)  run decomposition based methods  vertical and horizontal run graph (Burge 1998)  region decomposition based methods  orientation map (Cao 2000) and wave aggregation (Delalandre 2003) run region

GREC 2003 : 31 July 2003Diapo 11 General Decomposition  step 1, object graph extraction (4)  meshes based methods, two steps (vaxivière 1995):  image is splited up into meshes  meshes are recognized according to a library  segmented based methods, two segmentations:  line, circle and ellipsis segmentation (Matas 1999) (Su 2002)  junction segmentation (Chen 2000) meshessegmented object

GREC 2003 : 31 July 2003Diapo 12 General Decomposition  step 2, mathematical approximation  vector, circle, and curve fitting (Rosin 1995)  step 3, high level object construction  circle reconstruction (Hilaire 2001)  contour matching (Zou 2000) (Ramel 2000) mathematical approximation circle reconstruction contour matching

GREC 2003 : 31 July 2003Diapo 13 General Decomposition  step 4, object graph correction, some examples:  pruning merging (Delalandre 2003)  junction fusion (Lin 2002)  vectorial correction (Hilaire 2001) junction fusion pruning & merging vectorial correction

GREC 2003 : 31 July 2003Diapo 14 Plan  Introduction  General Decomposition  Method Comparison  Method Combination  Conclusion

GREC 2003 : 31 July 2003Diapo 15 Method Comparison  object graph extraction, seven criteria: morphology junction invariance sensitivity semantic reversibility complexity best method tracking, run, region run, region skeletonisation, contouring object segmentation meshes, tracking, object segmentation region, run tracking, meshes Criterion  Junction:junction detection  Morphology:various shape analysis  Invariance:scale and orientation change  Sensitivity:noise resistance  Semantic:low or high level object  Reversibility:image return  Complexity:low algorithmic complexity

GREC 2003 : 31 July 2003Diapo 16 Plan  Introduction  General Decomposition  Method Comparison  Method Combination  Conclusion

GREC 2003 : 31 July 2003Diapo 17 Method Combination Analysis Recognition 1 Recognition 2 comparison  comparison combination  different analysis and recognition, then comparison   multi representation  skeletonisation and contouring (Nakajima 1999)

GREC 2003 : 31 July 2003Diapo 18 Method Combination  hybrid combination  different analysis, then hybrid graph construction and recognition   multi representation  run and skeleton graph (Xue 2001)  region graph and statistical description (Delalandre 2003) Analysis or Recognition Analysis or Recognition Hybrid construction

GREC 2003 : 31 July 2003Diapo 19 Method Combination  cooperative combination  first analysis in order to help the second analysis   process simplification  object simplification (Song 2002) Analysis or Recognition Analysis Recognition

GREC 2003 : 31 July 2003Diapo 20 Plan  Introduction  Global Structural Analysis  Local Structural Analysis  Method Combination  Conclusion

GREC 2003 : 31 July 2003Diapo 21 Conclusion  local structural analysis:  connected component  graph  4 main steps  7 criteria of comparison  method combination:  a research perspective   multi representation (structural and statistical-structural)   process simplification