Abstract

It is now generally accepted that depth information is processed by a set of mechanisms, each tuned to a restricted range of disparities. The contrast dependence of stereoacuity argues that these mechanisms are also tuned for contrast. Due to the resulting confounding of contrast and disparity, it should be possible to alter the perceived depth of a test pattern simply by changing its contrast. We tested this hypothesis with a series of depth matching experiments. Over the range of 10–100% contrast, perceived depth varies as a power law function of contrast. In addition, at low contrasts the test pattern always appears to be farther away than the 50% contrast comparison pattern, regardless of whether the test disparity is crossed or uncrossed. In other words, the test appears to have more depth than the comparison in the uncrossed case and less depth (closer to the fronto-parallel plane) than the comparison in the crossed case. Although the test pattern appears to be smaller than the comparison at low contrasts, control experiments indicate that this is not the result of inferring distance from size.

© 1991 Optical Society of America