Abstract

Human discrimination of edge curvature was investigated over a 2-decade range of curvatures. The luminance profile of the edge pattern was either sharp or blurred on a scale that varied over a range of almost 2 decades. The experiments with curved blurred stimuli can also be regarded as investigations of contrast discrimination in which a blurred bar is superimposed orthogonally upon a blurred edge. The discrimination thresholds for the blurred stimuli show substantial size invariance, which can be explained in terms of contrast discrimination and masking with orthogonally oriented patterns rather than in terms of curvature per se. No such size invariance is found with sharp stimuli. All results can be described by a simple model based only upon local contrast.

© 1995 Optical Society of America

Curvature and separation discrimination at texture boundaries

Hugh R. Wilson and Whitman A. Richards
J. Opt. Soc. Am. A 9(10) 1653-1662 (1992)

Mechanisms of contour curvature discrimination

Hugh R. Wilson and Whitman A. Richards
J. Opt. Soc. Am. A 6(1) 106-115 (1989)

Spatial alignment across gaps: contributions of orientation and spatial scale

Sarah J. Waugh and Dennis M. Levi
J. Opt. Soc. Am. A 12(10) 2305-2317 (1995)

Discrimination of contour curvature: data and theory

Hugh R. Wilson
J. Opt. Soc. Am. A 2(7) 1191-1199 (1985)

Contrast response of a movement-encoding system

Jüri Allik and Aleksander Pulver
J. Opt. Soc. Am. A 12(6) 1185-1197 (1995)