Spatial bandwidth of channels for slant estimated from complex gratings

Vertical sinusoidal gratings of slightly differing spatial frequencies presented to each eye lead to the perception of a slanted plane. If a complex pattern is created by presenting two different frequencies to one eye, while the other eye views an increment of one of those frequencies and a decrement of the other, then the stimulus is equivalent to two superimposed vertical planes slanted in opposite directions. Yet the observer generally sees only a single surface at a slant intermediate to the possible extremes. As the relative spatial-frequency content of the two opposing planes is varied, the observed slant is a measure of the strengths of the connecting interactions of the underlying stereomechanisms. From these data the bandwidth of the monocular input channels for the binocular slant mechanism can be estimated and is found to be about two octaves.