Abstract

We measured thresholds for two-line resolution and for two-line separation discrimination in central and peripheral vision using Gaussian blurred lines. For both tasks and at all eccentricities the dependence of thresholds on stimulus blur can be characterized as follows: Th = [U* (1 + B_s/B_E)²])^1/2, where Th is the threshold, U is the unblurred threshold, B_S is the stimulus blur, and BE is the equivalent intrinsic blur of the visual system. When the stimulus blur B_S is small, it has no influence on the thresholds; when it is larger than the equivalent intrinsic blur B_E the threshold is proportional to the stimulus blur. B_E is contrast invariant.

© 1987 Optical Society of America