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Proceedings Paper

A gaze-contingent display to study contrast sensitivity under natural viewing conditions
Author(s): Michael Dorr; Peter J. Bex
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Paper Abstract

Contrast sensitivity has been extensively studied over the last decades and there are well-established models of early vision that were derived by presenting the visual system with synthetic stimuli such as sine-wave gratings near threshold contrasts. Natural scenes, however, contain a much wider distribution of orientations, spatial frequencies, and both luminance and contrast values. Furthermore, humans typically move their eyes two to three times per second under natural viewing conditions, but most laboratory experiments require subjects to maintain central fixation. We here describe a gaze-contingent display capable of performing real-time contrast modulations of video in retinal coordinates, thus allowing us to study contrast sensitivity when dynamically viewing dynamic scenes. Our system is based on a Laplacian pyramid for each frame that efficiently represents individual frequency bands. Each output pixel is then computed as a locally weighted sum of pyramid levels to introduce local contrast changes as a function of gaze. Our GPU implementation achieves real-time performance with more than 100 fps on high-resolution video (1920 by 1080 pixels) and a synthesis latency of only 1.5ms. Psychophysical data show that contrast sensitivity is greatly decreased in natural videos and under dynamic viewing conditions. Synthetic stimuli therefore only poorly characterize natural vision.

Paper Details

Date Published: 3 February 2011
PDF: 8 pages
Proc. SPIE 7865, Human Vision and Electronic Imaging XVI, 78650Y (3 February 2011); doi: 10.1117/12.872502
Show Author Affiliations
Michael Dorr, Schepens Eye Research Institute, Harvard Medical School (United States)
Peter J. Bex, Schepens Eye Research Institute, Harvard Medical School (United States)


Published in SPIE Proceedings Vol. 7865:
Human Vision and Electronic Imaging XVI
Bernice E. Rogowitz; Thrasyvoulos N. Pappas, Editor(s)

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