Accession Number : ADD011776

Title :   Measurement of Visual Contrast Sensitivity.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Von Gierke,H E ; Marko,A R

Report Date : 16 Apr 1985

Pagination or Media Count : 10

Abstract : This invention involves measurement of the visual contrast sensitivity (modulation transfer) function of a human subject by means of linear or circular spatial frequency pattern on a cathode ray tube whose contrast is automatically decreasing or increasing depending on the subject pressing or releasing a hand-switch button. The threshold of detection of the pattern modulation is found by the subject by adjusting the contast to values which vary about the subject's threshold thereby determining the threshold and also providing by the magnitude of the contrast fluctuations between reversals some estimate of the variability of the subject's absolute threshold. The invention also involves the slow automatic sweeping of the spatial frequency of the pattern over the spatial frequencies after preset time intervals or after threshold has been defined at each frequency by a selected number of subject-determined threshold crossings; i.e., contrast reversals. (Author)

Descriptors :   *PATENTS, *OPTOMETERS, *VISUAL PERCEPTION, *CONTRAST, THRESHOLDS(PHYSIOLOGY), SENSITIVITY, MEASUREMENT, PERFORMANCE(HUMAN), TIME INTERVALS, PATTERNS, SPATIAL DISTRIBUTION, CATHODE RAY TUBE SCREENS, FREQUENCY, MODULATION, TRANSFER, PLOTTING

Subject Categories : Anatomy and Physiology
      Electrooptical and Optoelectronic Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE