Perceiving Perpendicular and Parallel Contours in the Frontoparallel Plane

Abstract

The perception of a pair of contours in a retinal image cannot be understood simply by adding up the perceptions of the individual contours. We compared the perception of configurations of contours in three psychophysical experiments. The results of the experiments were analyzed so that the quantitative comparison of the perceived configurations was possible. Thresholds estimated were substantially lower from a perpendicular junction than from a single contour or from a non-perpendicular junction. The lowest thresholds were observed from a pair of parallel contours. The results suggest that the visual system is sensitive to perpendicular junctions and parallel contours in a retinal image.