Abstract

A stationary pitched visual field generates deviations of the elevation of visually perceived eye level (VPEL) ≅ 0.6 × the pitch angle; deviations are as large if the field consists of a single line pitched from vertical in darkness as if the field is complexly structured. Horizontal lines have minimal influence.¹ In psychophysical measurements with fields pitched between −30° and +20° we obtain linear summation of influences on VPEL from two pitched from vertical lines; summation is identical whether the lines are adjacent or separated by 60°. The following model relates known cortical neurophysiology to observer centered spatial localization and accounts for the results: Employing a spherical approximation to the eye in primary viewing position, the influence on VPEL derives from the location of the intersection point (IP) of the great circle (GC) containing the image of a straight line with the central vertical retinal meridian (CVRM). Summation of influences on VPEL occurs in V1 among neural units whose orientations serve a single retinal GC and across members of GCs with a commom IP on the CVRM. Pitching an erect frontoparallel plane by θ° shifts the IPs of the GCs containing the images of a set of vertical lines from the upper and lower poles by θ° on the CVRM, and leads to outputs from different neural processors uniquely related to visual pitch.

© 1989 Optical Society of America