Oxyopia Abstract

September 14, 2007
Friday, 4:00 PM
489 Minor Hall

Alan Gilchrist, PhD
Professor, Department of Psychology, Rutgers University
Host: Steve Palmer

Title

Frames of reference in the computation of lightness

Abstract

In computing the surface lightness of objects, the human visual system behaves as if it is taking the illumination level into account, although the way this is done has not been explained concretely. I will report a series of experiments in which observers match the lightness of gray probe disks, which are inserted into scenes containing different levels of illumination. The results suggest that complex scenes are segmented into functional frames of reference that represent regions of common illumination. I will also discuss the failure of spatial filtering approaches to account for these findings, the factors used to segment the image into frameworks, the grouping of non-adjacent regions of the retinal image into frameworks, and the nature of crosstalk between adjacent frameworks.

[Back to Gilchrist - Oxyopia Page]