title: The perceived strength of motion-defined edges.
abstract: Performance on visual tasks involving the use of motion-defined contours is likely to depend on stimulus strength, but presently there are no empirical or experimental assessments of motion-defined contour strength. Therefore, a matching method was used to estimate the strength of suprathreshold motion-defined edges on a luminance-contrast scale. The perceived strength of a motion-defined contour was expressed as an equivalent luminance contrast; this allowed the use of a single scale which accommodates diverse motion-defined stimuli. Motion-defined edge strength estimated in this manner was an inverted U-shaped function of dot density and dot velocity, and spanned at least a fivefold range of edge strengths. For one observer, maximum motion-defined edge strength was equivalent to 79% luminance contrast, at least thirteen times the contrast detection threshold. The results are interpreted via a simple two-stage model for perceiving motion-defined edges.
authors.affiliation: College of Optometry, University of Houston, TX 77204-6052.
authors.forename: T
authors.initials: T
authors.lastname: Banton
authors.forename: D M
authors.initials: DM
authors.lastname: Levi
mesh_terms: D015350:Contrast Sensitivity; D006801:Humans; D009039:Motion Perception; D010775:Photic Stimulation