Accession Number:

ADA254093

Title:

Perception of Lightness and Brightness in Complex Patterns

Descriptive Note:

Annual rept. 1 May 91-30 Apr 92,

Corporate Author:

EYE RESEARCH INST OF RETINA FOUNDATION BOSTON MA

Personal Author(s):

Report Date:

1992-06-30

Pagination or Media Count:

23.0

Abstract:

Perception of surface color plays important part in many everyday visual tasks. Psychophysical and neurophysiological data on early visual processes suggest a number of potential sensory limitations on the accuracy of surface-color perception. A new paradigm has been used to clarify the relationships between early visual processes and perception of achromatic surface colors shades of gray. Psychophysical measurements of perceived surface color were made using achromatic stimulus patterns that were complex enough to support unambiguous perception of surfaces and lights. Lightness apparent reflectance, brightness apparent luminance and local brightness contrasts were all measured using the same stimulus patterns. According to a number of models, lightness is closely related to local brightness contrast, but the data indicated that the relationship is more complicated than previously supposed. The brightness contrast data are well described by Stiles threshold- vs-radiance curve, which is widely thought to be a characteristic of retinal adaptation processes. Both brightness and lightness are slightly higher on dark gray backgrounds than on white backgrounds. This perceptual error appear to be independent of illumination level.

Subject Categories:

  • Psychology
  • Anatomy and Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE