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 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

6. Illuminant
Surfaces
Photoreceptor Array

7. Surface Color Algorithms
Maloney (1999)

8. Cues to the Illuminant Reference Surfaces Subspace Constraints
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)

9. UNIFORM BACKGROUND CUE

10. SPECULAR HIGHLIGHT CUE

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

12. SHADOW EDGE CUE
D’Zmura (1992)

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

14. 2. Perturbation Methods

15. Perturbation Methods target A base D65 perturbed
Specular information perturbed …..
Yang, Maloney & Landy, ARVO, 1999

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

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

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

19. v’ u’ CHF GT EC BRM Yang, Maloney & Landy, ARVO, 1999 0.52 0.45 0.52 u’
Yang, Maloney & Landy, ARVO, 1999

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

21. 3. Methods

22. Multi-Channel Rendering1
N = 12
RADIANCE
Larson (1992) l

23. Stimulus Stereo Pairs
D65 A
RADIANCE

25. SHADOW EDGE CUE
D65

26. SHADOW EDGE CUE A

27. SHADOW EDGE CUE
Perturbed

28. Perturbation Methods target A base D65 perturbed
Specular information perturbed …..

29. Achromatic Matching

30. 4. Results

31. D A
D A GT GT v’
0.52
0.45 v’
0.52
0.45 u’ u’

32. D A
D A
JLS
JLS v’
0.52
0.45 v’
0.52
0.45 u’ u’

33. D A
D A
JNY
JNY v’
0.52
0.45 v’
0.52
0.45 u’ u’

34. 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

36. D A
A D65

37. Photoreceptor Excitations