Accession Number : ADA192207

Title :   Interactions between Brief Flashed Lines at Threshold.

Descriptive Note : Final rept. 1978-1987,

Corporate Author : NEW HAMPSHIRE UNIV DURHAM VISION RESEARCH LAB

Personal Author(s) : Smith, Robert A

PDF Url : ADA192207

Report Date : 11 Dec 1987

Pagination or Media Count : 95

Abstract : Our results are concentrated in seven basic areas: 1) We find that masking is subject to considerable learning effects. Weber's Law is only observed--when proper controls are used--in the relatively uninteresting case where it is inherent in the stimulus, and is unaffected by visual physiology. 2) There is a region of space/time separations wherein two flashed lines will show lateral facilitation, rather than inhibition, suggesting the action of a motion-detector. 3) substantial modelling of line interactions confirmed our conclusion that this facilitation was a nonlinear effect, and not predictable from current probability-summation models. 4) Spatial summation and 2-line acuity change very differential with retinal eccentricity; it may be that one taps primarily receptor size while the other taps receptor separation. 5) It is possible to observe visual aliasing in the parafovea without the use of interference fringes. This aliasing appears to be neural, rather than receptoral. 6) Flashed presentations produce a large transient change in the area of spatial summation and in the amount of lateral inhibition. Keywords: Vision; Visual masking; Spatial sampling; Spatial summation; Motion detection.

Descriptors :   *MOTION, *OPTICAL IMAGES, *SPACE PERCEPTION, DETECTION, ECCENTRICITY, INTERFERENCE GUARD BAND, MASKING, NONLINEAR SYSTEMS, PHYSIOLOGY, RETINA, SAMPLING, SENSE ORGANS, SEPARATION, SIZES(DIMENSIONS), TAPS, TRANSIENTS, VISION, IMAGE PROCESSING, PATTERN RECOGNITION, THRESHOLDS(PHYSIOLOGY)

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE