Color as a source of information in the stereo correspondence process.

Although previous research has shown that depth perception is weak for isoluminant stereograms, the possibility remains that color plays an important role in stereopsis when luminance variations are present. To examine this possibility, we measured the relative contribution of chromatic and luminance cues in solving the correspondence problem for ambiguous "wallpaper" stereograms composed of vertical bars. Using an ideal-observer analysis, we found that chromatic cues were used much more efficiently than luminance cues in disambiguating these stereograms when the patterns were presented on a dark background but were used with about equal efficiency when presented on a light background. Another experiment (using the same wallpaper patterns) showed that chromatic and luminance cues were also used with about equal efficiency in a standard stereo detection task. Some of the implications of these results for theories of stereo vision are discussed.