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Object Recognition: History and Overview

Object Recognition: History and Overview. Slides adapted from Fei-Fei Li, Rob Fergus, Antonio Torralba, and Jean Ponce. How many visual object categories are there?. ~10,000 to 30,000. Biederman 1987. ~10,000 to 30,000. OBJECTS. INANIMATE. ANIMALS. PLANTS. NATURAL. MAN-MADE. ….

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Object Recognition: History and Overview

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  1. Object Recognition: History and Overview Slides adapted from Fei-Fei Li, Rob Fergus, Antonio Torralba, and Jean Ponce

  2. How many visual object categories are there? ~10,000 to 30,000 Biederman 1987

  3. ~10,000 to 30,000

  4. OBJECTS INANIMATE ANIMALS PLANTS NATURAL MAN-MADE ….. VERTEBRATE MAMMALS BIRDS TAPIR BOAR GROUSE CAMERA

  5. So what does object recognition involve?

  6. Scene categorization • outdoor • city • …

  7. Image-level annotation: are there people? • outdoor • city • …

  8. Object detection: where are the people?

  9. Image parsing mountain tree building banner street lamp vendor people

  10. Modeling variability Variability: Camera position Illumination Shape parameters Within-class variations?

  11. Within-class variations

  12. q Camera position Illumination Variability: Alignment Shape: assumed known Roberts (1965); Lowe (1987); Faugeras & Hebert (1986); Grimson & Lozano-Perez (1986); Huttenlocher & Ullman (1987)

  13. xi xi ' T Recall: Alignment • Alignment: fitting a model to a transformation between pairs of features (matches) in two images Find transformation Tthat minimizes

  14. Recall: Origins of computer vision L. G. Roberts, Machine Perception of Three Dimensional Solids, Ph.D. thesis, MIT Department of Electrical Engineering, 1963.

  15. Alignment: Huttenlocher & Ullman (1987)

  16. Invariance to: Variability Camera position Illumination Internal parameters Duda & Hart ( 1972); Weiss (1987); Mundy et al. (1992-94); Rothwell et al. (1992); Burns et al. (1993)

  17. Projective invariants (Rothwell et al., 1992): Recall: invariant to similarity transformations computed from four points B C D A General 3D objects do not admit monocular viewpoint invariants (Burns et al., 1993)

  18. Representing and recognizing object categories is harder... ACRONYM (Brooks and Binford, 1981) Binford (1971), Nevatia & Binford (1972), Marr & Nishihara (1978)

  19. Recognition by components Geons (Biederman 1987) ???

  20. General shape primitives? Generalized cylinders Ponce et al. (1989) Forsyth (2000) Zisserman et al. (1995)

  21. Empirical models of image variability Appearance-based techniques Turk & Pentland (1991); Murase & Nayar (1995); etc.

  22. Eigenfaces (Turk & Pentland, 1991)

  23. Color Histograms Swain and Ballard, Color Indexing, IJCV 1991.

  24. Appearance manifolds H. Murase and S. Nayar, Visual learning and recognition of 3-d objects from appearance, IJCV 1995

  25. Limitations of global appearance models • Requires global registration of patterns • Not robust to clutter, occlusion, geometric transformations

  26. Turk and Pentland, 1991 Belhumeur, Hespanha, & Kriegman, 1997 Schneiderman & Kanade 2004 Viola and Jones, 2000 Sliding window approaches • Schneiderman & Kanade, 2004 • Argawal and Roth, 2002 • Poggio et al. 1993

  27. Sliding window approaches • Scale / orientation range to search over • Speed • Context

  28. Local features Combining local appearance, spatial constraints, invariants, and classification techniques from machine learning. Lowe’02 Schmid & Mohr’97 Mahamud & Hebert’03

  29. Local features for recognition of object instances

  30. Local features for recognition of object instances • Lowe, et al. 1999, 2003 • Mahamud and Hebert, 2000 • Ferrari, Tuytelaars, and Van Gool, 2004 • Rothganger, Lazebnik, and Ponce, 2004 • Moreels and Perona, 2005 • …

  31. Representing categories: Parts and Structure Weber, Welling & Perona (2000), Fergus, Perona & Zisserman (2003)

  32. Parts-and-shape representation • Model: • Object as a set of parts • Relative locations between parts • Appearance of part Figure from [Fischler & Elschlager 73]

  33. Object Bag-of-features models Bag of ‘words’

  34. Objects as texture • All of these are treated as being the same • No distinction between foreground and background: scene recognition?

  35. Timeline of recognition • 1965-late 1980s: alignment, geometric primitives • Early 1990s: invariants, appearance-based methods • Mid-late 1990s: sliding window approaches • Late 1990s: feature-based methods • Early 2000s: parts-and-shape models • 2003 – present: bags of features • Present trends: combination of local and global methods, modeling context, emphasis on “image parsing”

  36. Global scene context • The “gist” of a scene: Oliva & Torralba (2001) http://people.csail.mit.edu/torralba/code/spatialenvelope/

  37. J. Hays and A. Efros, Scene Completion using Millions of Photographs, SIGGRAPH 2007

  38. Scene-level context for image parsing J. Tighe and S. Lazebnik, ECCV 2010 submission

  39. Geometric context D. Hoiem, A. Efros, and M. Herbert. Putting Objects in Perspective. CVPR 2006.

  40. What “works” today • Reading license plates, zip codes, checks

  41. What “works” today • Reading license plates, zip codes, checks • Fingerprint recognition

  42. What “works” today • Reading license plates, zip codes, checks • Fingerprint recognition • Face detection

  43. What “works” today • Reading license plates, zip codes, checks • Fingerprint recognition • Face detection • Recognition of flat textured objects (CD covers, book covers, etc.)

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