Interação entre os mecanismos cromático e acromático na Cromoestereopsia

Abstract

In order to know if the mechanisms that process luminance are independent of those that process colour, or, conversely, if there is an interaction between them, we have executed two experiments. In the first, we studied how the changes in the perception of depth elicited by chromostereopsis with couples of isoluminants and anisochromatic patches inserted in a uniform background, which varied in luminance from trial to trial. In a second experiment, we used a square-wave grating background, in which every strip changes the luminance of the colour. The different background could be, on the one hand, isoluminant/anisoluminant, or, on the other hand, isochromatic/anisochromatic. The results showed: 1) that perceived depth varied as a function of the luminance variation. That is, reversing the depth when the sign of the difference in luminance between figure and background changes; 2) that it is possible to elicit chromoesteropsis at isoluminance; 3) a weak interaction between the variation of chromatic contrast and achromatic contrast; 4) that interactions between the two mechanisms should occur at pre-retinal levels; and 5) the responses of the two mechanisms are separable.