A model for motion sharpening: contrast gain control precedes compressive nonlinearity

Barbieri-Hesse, Gillian S., Georgeson, Mark A., Hammett, Stephen T. and Bedingham, Samantha (2003). A model for motion sharpening: contrast gain control precedes compressive nonlinearity. IN: Human Vision--When It Works and When It Fails. 7th Applied Vision Association Christmas Meeting. 2002-12-08. (Unpublished)

Abstract

Blurred edges appear sharper in motion than when they are stationary. We have previously shown how such distortions in perceived edge blur may be explained by a model which assumes that luminance contrast is encoded by a local contrast transducer whose response becomes progressively more compressive as speed increases. To test this model further, we measured the sharpening of drifting, periodic patterns over a large range of contrasts, blur widths, and speeds Human Vision. The results indicate that, while sharpening increased with speed, it was practically invariant with contrast. This contrast invariance cannot be explained by a fixed compressive nonlinearity since that predicts almost no sharpening at low contrasts.We show by computational modelling of spatiotemporal responses that, if a dynamic contrast gain control precedes the static nonlinear transducer, then motion sharpening, its speed dependence, and its invariance with contrast can be predicted with reasonable accuracy.

Divisions: Life & Health Sciences > Optometry
Additional Information: Human Vision--When It Works and When It Fails. Seventh Abstract published in Applied Vision Association Christmas Meeting Aston University, Birmingham, UK, 18 December 2002, Abstracts. Perception, (2003), 32 (3), p.385-386, 0301-0066.
Event Title: Human Vision--When It Works and When It Fails. 7th Applied Vision Association Christmas Meeting
Event Type: Other
Event Dates: 2002-12-08
Uncontrolled Keywords: blurred edges,motion,distortions,perceived edge blur,luminance contrast,local contrast transducer,sharpening of drifting,periodic patterns,contrasts
["eprint_fieldopt_dates_date_type_" not defined] Date: 2003
Authors: Barbieri-Hesse, Gillian S.
Georgeson, Mark A. ( 0000-0002-8173-9522)
Hammett, Stephen T.
Bedingham, Samantha

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