Recovering depth-order from orientation-defined junctions.

This study investigated how visual systems recover depth-order from orientation-defined junctions. Stimuli were superimposed stripes defined by Gabor micro-patterns (Gabors). In one stripe (random stripe), Gabor orientation was randomly selected from a given range, while in the other (constant stripe) it was selected so as to be different from the mean orientation of the random stripe by 90 degrees . Observers reported which of the two stripes, the right- or left-tilted one, they perceived as "nearer" than the other. Observers frequently reported that the random stripe was nearer than the constant stripe. The results appeared to stem from detection of discontinuity of texture edges of the constant stripe due to masking by the random stripe at junctions. This idea was confirmed in the following experiments where discontinuity of the texture edges at junctions was introduced by changing the Gabor luminance contrast in one stripe but keeping it intact in the other. The results indicated that processing of texture edges at junctions can contribute to the perception of depth-order.