Visual Neuroscience


Three-dimensional shape perception from chromatic orientation flows

QASIM  ZAIDI  a1 c1 and ANDREA  LI  a2
a1 SUNY College of Optometry, Department of Vision Sciences, New York, New York
a2 Queens College, CUNY, Department of Psychology, Flushing, New York

Article author query
zaidi q   [Google Scholar] 
li a   [Google Scholar] 


The role of chromatic information in 3-D shape perception is controversial. We resolve this controversy by showing that chromatic orientation flows are sufficient for accurate perception of 3-D shape. Chromatic flows required less cone contrast to convey shape than did achromatic flows, thus ruling out luminance artifacts as a problem. Luminance artifacts were also ruled out by a protanope's inability to see 3-D shape from chromatic flows. Since chromatic orientation flows can only be extracted from retinal images by neurons that are responsive to color modulations and selective for orientation, the psychophysical results also resolve the controversy over the existence of such neurons. In addition, we show that identification of 3-D shapes from chromatic flows can be masked by luminance modulations, indicating that it is subserved by orientation-tuned neurons sensitive to both chromatic and luminance modulations.

(Received August 26 2005)
(Accepted January 3 2006)

Key Words: Three-dimensional shape; Color; Orientation flows.

c1 Address correspondence and reprint requests to: Qasim Zaidi, SUNY College of Optometry, Department of Vision Sciences, 33 W 42nd Street, New York, NY 10036, USA. E-mail: