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S URFACE C OLOR AND S HADOWS T ESTING THE D’Z MURA- I VERSON M ODEL

S URFACE C OLOR AND S HADOWS T ESTING THE D’Z MURA- I VERSON M ODEL Laurence T. Maloney Joong Nam Yang Psychology and Neural Science Visual Sciences Center New York University University of Chicago. ARVO 2000 May 3, 2000

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S URFACE C OLOR AND S HADOWS T ESTING THE D’Z MURA- I VERSON M ODEL

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  1. SURFACE COLOR AND SHADOWS TESTING THE D’ZMURA-IVERSON MODEL Laurence T. Maloney Joong Nam Yang Psychology and Neural Science Visual Sciences Center New York University University of Chicago ARVO 2000 May 3, 2000 Ft. Lauderdale, Florida

  2. 1. Cues to the Illuminant

  3. Surface Color Perception • [I]n our observations with the sense of • vision, we always start out by forming a • judgment about the colours of bodies, • eliminating the differences of illumination • by which a body is revealed to us. • von Helmholtz

  4. Illuminant Chromaticity

  5. Illuminant Surfaces Photoreceptor Array

  6. Surface Color Algorithms Maloney (1999)

  7. Cues to the Illuminant Reference Surfaces Brill (1978) Buchsbaum (1980) Subspace Constraints Maloney & Wandell (1986) D’Zmura & Iverson (1993) Chromatic Aberration Funt & Ho (1990) and more ……. Specularity Lee (1986) D’Zmura & Lennie (1986) Mutual Illumination Drew & Funt (1990) Shadow Edge Cue D’Zmura & Iverson (1994) Maloney (1999)

  8. UNIFORM BACKGROUND CUE

  9. SPECULAR HIGHLIGHT CUE

  10. D’ZMURA-LENNIE-LEE CUE Matte Contamination Problem Specular Matte 1 Matte 2

  11. SHADOW EDGE CUE D’Zmura (1992)

  12. Uniform Background DZ-D-L Specularity Specular Highlight Illuminant Cue Combination Cue Promotion Illuminant Estimate Scene Shadow Dynamic Re-Weighting Maloney (1999)

  13. 2. Perturbation Methods

  14. target A baseD65perturbed Perturbation Methods Specular information perturbed ….. Yang, Maloney & Landy, ARVO, 1999

  15. JNY ? Target A Base D65 v’ Perturbed Illuminant D65 (matte) Illuminant A (specular) u’

  16. JNY ? Target A Base D65 v’ Perturbed Illuminant D65 (matte) Illuminant A (specular) u’

  17. JNY ? Target A Base D65 v’ Perturbed Illuminant D65 (matte) Illuminant A (specular) u’

  18. 0.52 0.45 CHF GT v’ 0.52 0.45 EC BRM 0.16 0.20 0.24 0.16 0.20 0.24 u’ Yang, Maloney & Landy, ARVO, 1999

  19. Average Scene Chromaticity CHF V’ u’ Yang, Maloney & Landy, ARVO, 1999

  20. 3. Methods

  21. Multi-Channel Rendering 1 N = 12 RADIANCE Larson (1992) 0 400 l 700

  22. Stimulus Stereo Pairs D65 A RADIANCE

  23. SHADOW EDGE CUE D65

  24. SHADOW EDGE CUE A

  25. SHADOW EDGE CUE Perturbed

  26. Perturbation Methods target A baseD65perturbed Specular information perturbed …..

  27. Achromatic Matching

  28. 4. Results

  29. 0.52 0.45 0.52 0.45 v’ v’ D65 A D65 A GT GT 0.16 0.20 0.24 0.16 0.20 0.24 u’ u’

  30. 0.52 0.45 0.52 0.45 v’ v’ D65 A D65 A JLS JLS 0.16 0.20 0.24 0.16 0.20 0.24 u’ u’

  31. 0.52 0.45 0.52 0.45 v’ v’ D65 A D65 A JNY JNY 0.16 0.20 0.24 0.16 0.20 0.24 u’ u’

  32. SUMMARY There are several candidate illuminant cues. A specularity cue influences human color vision (Yang, Maloney & Landy, 1999). The shadow edge cue does not influence human color vision, for our choice of scene. Supported by NIH/NEI EY08266

  33. D65 A A D65

  34. Photoreceptor Excitations

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