Accession Number : AD0666045

Title :   EXPERIMENTAL STUDY OF THE EFFECTS OF SURROUND BRIGHTNESS AND SIZE ON VISUAL PERFORMANCE.

Descriptive Note : Final rept. 1 Mar 66-1 Mar 67,

Corporate Author : RADIO CORP OF AMERICA MOORESTOWN N J SYSTEMS ENGINEERING EVALUATION AND RESEARCH

Personal Author(s) : Ireland,Fred H. ; Kinslow,William E. ; Lewin,Edwin ; Page,Donald E.

Report Date : SEP 1967

Pagination or Media Count : 57

Abstract : A visual display must often be used in a setting where the surrounding visual field is brighter than the background area within the display. Such use violates a common human factors recommendation that the brightness of the display surround should be equal to, or slightly less than, that of the background in the display itself. The purpose of this experiment was to determine, quantitatively, the degradation in visibility due to high surround brightness and thus to provide useful data for the display system designer. Measurements were made of the target-to-background contrast required for each of 5 Ss to determine, with 50% accuracy, the orientation of a light Landolt ring target centered on a darker circular background. The target gap subtended 1.93 minutes of arc. Background angular subtense was varied from 5 degrees to 45 degrees, background brightness from 0.17 to 18.43 millilamberts and surround-to-background brightness ratio from 0:1 to 100:1. A uniform surround, independently variable in brightness with respect to the background, filled the rest of the visual field. The scene was viewed monocularly with natural pupil. The contrast limen was found to vary directly with surround-to-background brightness ratio for ratios greater than one. The variation with background size was smaller than predicted by an equation for integrating the effects of point sources of glare. An apparent tendency for a slight increase in limen as the surround-to-background ratio decreased from 1:1 to 0:1 was not statistically significant. Results are described by equations, and a procedure for their practical application is illustrated. (Author)

Descriptors :   (*DISPLAY SYSTEMS, BRIGHTNESS), (*HUMAN FACTORS ENGINEERING, DISPLAY SYSTEMS), BACKGROUND, VISIBILITY, PERFORMANCE(HUMAN), VISUAL ACUITY, ILLUMINATION, COCKPITS, EXPERIMENTAL DESIGN, MATHEMATICAL ANALYSIS

Subject Categories : Human Factors Engineering & Man Machine System

Distribution Statement : APPROVED FOR PUBLIC RELEASE