Effect of exposure duration, contrast and base blur on coding and discrimination of edges.

Full Abstract

We extend a neural network model, developed to examine neural correlates for the dynamic synthesis of edges from luminance gradients (Ogmen, 1993), to account for the effects of exposure duration, base blur and contrast on the perceived sharpness of edges. This model of REtino-COrtical Dynamics (RECOD) predicts that (i) a decrease in exposure duration causes an increase in the perceived blur and the blur discrimination threshold for edges, (ii) this increase in perceived blur is more pronounced for sharper edges than for blurred edges, (iii) perceived blur is independent of contrast while the blur discrimination threshold decreases with contrast, (iv) perceived blur increases with increasing base blur while the blur discrimination threshold has a nonmonotonic U-shaped dependence on base blur, (v) the perceived location of an edge shifts progressively towards the low-luminance side of the edge with increasing contrast, and (vi) perceived contrast of suprathreshold stimuli is essentially independent of spatial frequency over a wide range of contrast values. These predictions are shown to be in quantitative agreement with existing psychophysical data from the literature and with data collected on three observers to quantify the effect of exposure duration on perceived blur.

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Author information

Author/s: Purushothaman, Gopathy (G); Lacassagne, Dominique (D); Bedell, Harold E (HE); Ogmen, Haluk (H);

Affiliation: Department of Electrical and Computer Engineering, University of Houston, TX 77204-4005, USA.

Journal and publication information

Publication Type: Journal Article

Journal: Spatial vision (Spat Vis), published in Netherlands. (Language: eng)

Reference: 2002-; vol 15 (issue 3) : pp 341-76

Dates: Created 2002/07/15; Completed 2003/01/10; Revised 2004/11/17;

PMID: 12116994, status: MEDLINE (last retrieval date: 11/6/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Contrast Sensitivity - physiology
Discrimination (Psychology) - physiology
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