Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

Mechanisms of contour curvature discrimination

Not Accessible

Your library or personal account may give you access

Abstract

Visual processing of contour curvature was investigated by measuring increment thresholds for curvatures from 0.31 to 25.4 deg−1. Curvature discrimination was assessed for three classes of stimuli: simple curved contours, high-frequency bandpass-filtered contours, and low-pass-filtered contours. High-frequency bandpass filtering had no effect on discrimination at low curvatures and only a modest effect at high curvatures. In contrast, low-pass filtering caused substantial threshold elevations at all curvatures. Thus the data lead to the surprising conclusion that high-spatial-frequency, orientation-selective mechanisms dominate curvature processing over the entire range of curvatures tested, a conclusion at odds with previous suggestions that large, low-spatial-frequency filters are involved in analyzing low curvatures. The data are explained accurately by a two-process model for curvature extraction: at high curvatures the local-processing model proposed by Wilson [ J. Opt. Soc. Am. A. 2, 1191 ( 1985)] fits the data well, whereas at low curvatures orientations are compared at points displaced a fixed distance along the tangent to the curve.

© 1989 Optical Society of America

Full Article  |  PDF Article
More Like This
Discrimination of contour curvature: data and theory

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

Curvature and separation discrimination at texture boundaries

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

Edge-curvature discriminability argues against explicit curvature detectors

Erik de Haan
J. Opt. Soc. Am. A 12(2) 202-213 (1995)

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (11)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Equations (7)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved