Contrast sensitivity function for stereopsis.

Contrast thresholds for stereopsis from narrow-band-filtered random-dot stereograms were compared with contrast thresholds for simple detection of similar narrow-band noise. Centre frequencies of filters were in the range 2.5--15 cycles deg(-1). It was found that the contrast sensitivity function for stereopsis is similar in shape to that for detection, suggesting that as far as contrast requirements are concerned the mechanisms of global stereopsis do not show a bias in sensitivity to any particular spatial frequency but instead require a constant level of suprathreshold contrast regardless of spatial frequency.