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Michael Langer Heinrich Bülthoff NEC Research Institute MPI for Biological Cybernetics Princeton, NJ Tübingen, Germany.
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Michael Langer Heinrich Bülthoff NEC Research Institute MPI for Biological Cybernetics Princeton, NJ Tübingen, Germany Shape from Shading under diffuse lighting: does dark mean deep? Presentation at the European Conference on Visual Perception, Oxford, U.K, August 1998
SFS on a Sunny Day L N(x) I(x) = N(x) L
SFS on a Sunny Day I(x) = N(x) L
SFS on a Cloudy Day (x)
SFS under Diffuse Lighting I(x) N(x) L dL (x) (x) = angle of visible light source
SFS under Diffuse Lighting Does Dark Means Deep?
Does Dark Means Deep? local intensity maximum
intensity anti-correlated correlated _ + depth _ + Height-Intensity Correlation
1 0.8 0.6 0.4 0.2 0 Which is higher ? N=17 percent correct _ + Correlation
1 0.8 0.6 0.4 0.2 0 Which is brighter ? height N=10 brightness percent correct _ + Correlation
Computational Modeling I(x) = (x) (Langer and Zucker ‘93) I(x) = N(x) L d L (x) (Stewart and Langer ‘96)
+ - + - + - Human - Models 1 0.8 0.6 percent correct 0.4 0.2 0 human LZ ‘93 SL ‘96
Conclusion • “Dark-means-deep” cannot account for shape-from-shading perception under diffuse lighting. • Point source models are insufficient. • Our visual system uses a more accurate physical model which is based on the angle of the visible light source.