Accession Number : AD0777853

Title :   A Measurement of the Anisotropic Modulation Transfer Function of the Extrafoveal Human Visual System.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING

Personal Author(s) : Cowger,Ronald I.

Report Date : DEC 1973

Pagination or Media Count : 422

Abstract : The anisotropy of the extrafoveal modulation transfer function (MTF) of the human visual system was measured at angles up to 45 degrees of eccentricity. The stimuli consisted of sine wave gratings of four different spatial frequencies which were presented at four different orientations. The results are presented as a series of plots depicting contrast sensitivity as a function of stimulus orientation and contrast sensitivity as a function of stimulus position in the visual field. The contrast sensitivity of all subjects was found to decrease more rapidly with increased stimulus eccentricity in the superior direction than in the nasal direction. The two predominant anisotropic effects that were observed are designated 'oblique effect' and 'depressed orthogonal' MTFs. Each type is described in detail and its occurrence analyzed. (Modified author abstract)

Descriptors :   *Psychophysics, *Visual perception, Anisotropy, Sine waves, Stimuli, Sensitivity, Psychophysiology, Orientation(Direction), Vision, Theses

Subject Categories : Psychology
      Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE