Accession Number:

ADA257934

Title:

Spatio-Temporal Masking: Hyperacuity and Local Adaptation

Descriptive Note:

Final rept. 1 Jan 1989-31 Jul 1992

Corporate Author:

CALIFORNIA UNIV BERKELEY SCHOOL OF OPTOMETRY

Personal Author(s):

Report Date:

1992-10-08

Pagination or Media Count:

9.0

Abstract:

a. Models of human vision were applied to image compression and image fidelity for both static and dynamic images. The role of the human observer in JPEG compression was clarified. The human observers visual information capacity was calculated to be about 20 bitsmin2, substantially higher than previous estimates. New formulas were developed for the Fourier transform of JPEG basis functions, connecting JPEG quantization matrices to the human observers contrast sensitivity function. Crawford masking was used to measure the visibility of lines and edges following abrupt luminance changes. The high frame rates produced higher temporal resolution than previous studies. A striking asymmetry between light and dark lines was found. b A robust test-pedestal framework was developed for modeling spatio-temporal vision with fewer assumptions than previous models. In this framework motion processing and hyperacuity thresholds are directly related to contrast processing. c A number of studies on motion processing developed new limits on the human visual systems capabilities. d In order to connect psychophysics results to underlying physiological mechanisms new techniques were developed for nonlinear analysis and source localization of visual evoked potentials and other biopotentials

Subject Categories:

  • Psychology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE