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Relative sensitivities to large-field optic-flow patterns varying in direction and speed

Edwards, Mark; Ibbotson, Michael

Description

Motion in depth results in radial optic-flow patterns. Forward motion results in radially expanding patterns, whereas backward motion generates contracting patterns. Radial optic-flow patterns are typically represented with a positive speed gradient, ie zero speed at the point of fixation, and maximum speed at the periphery. However, the actual speed profile in such a stimulus will depend upon the relative depth of objects in the scene. Using large-field stimuli (82 deg diameter) we determined...[Show more]

dc.contributor.authorEdwards, Mark
dc.contributor.authorIbbotson, Michael
dc.date.accessioned2015-12-08T22:23:04Z
dc.identifier.issn0301-0066
dc.identifier.urihttp://hdl.handle.net/1885/32712
dc.description.abstractMotion in depth results in radial optic-flow patterns. Forward motion results in radially expanding patterns, whereas backward motion generates contracting patterns. Radial optic-flow patterns are typically represented with a positive speed gradient, ie zero speed at the point of fixation, and maximum speed at the periphery. However, the actual speed profile in such a stimulus will depend upon the relative depth of objects in the scene. Using large-field stimuli (82 deg diameter) we determined relative sensitivities to radial expansion and contraction patterns and also to various types of speed gradients: positive, negative, random, and flat. We found that, even when large-field stimuli are used, observers are more sensitive to radially contracting patterns than to expanding patterns. Sensitivity to the positive speed gradient was not consistently different from either the negative or random gradients. Sensitivity to the flat gradient depended upon the speed of the stimuli. The finding of greater sensitivity to radial contraction is discussed in terms of the functional requirements involved in the use of optic-flow signals in maintaining balance. On the basis of the present findings, the utility of comparing psychophysical results based on thresholds against physiological data based on suprathreshold stimuli is also discussed.
dc.publisherPion Ltd
dc.sourcePerception
dc.subjectKeywords: article; body equilibrium; depth perception; human; male; methodology; movement perception; pattern recognition; perceptive threshold; photostimulation; physiology; psychophysics; retina; visual field; Depth Perception; Humans; Male; Motion Perception; Mu
dc.titleRelative sensitivities to large-field optic-flow patterns varying in direction and speed
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume36
dc.date.issued2007
local.identifier.absfor170112 - Sensory Processes, Perception and Performance
local.identifier.ariespublicationU9312950xPUB94
local.type.statusPublished Version
local.contributor.affiliationEdwards, Mark, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationIbbotson, Michael, College of Medicine, Biology and Environment, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.startpage113
local.bibliographicCitation.lastpage124
local.identifier.doi10.1068/p5626
dc.date.updated2015-12-08T08:49:34Z
local.identifier.scopusID2-s2.0-33847793407
CollectionsANU Research Publications

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