| Lines and dots: characteristics of the motion integration process. | |
| | |
MedLine Citation:
|
PMID: 11448713 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Local motion detectors can only provide the velocity component perpendicular to a moving line that crosses their receptive field, leading to an ambiguity known as the "aperture problem". This problem is solved exactly for rigid objects translating in the screen plane via the intersection of constraints (IOC). In natural scenes, however, object motions are not restricted to fronto-parallel translations, and several objects with distinct motions may be present in the visual space. Under these conditions the usual IOC construction is no longer valid, which raises questions as its use as a basis for spatial integration and selection of motion signals in uniform and non-uniform velocity fields. The influence of the motion of random dots on the perceived direction of a horizontal line grating was measured, when dots and lines are seen through different apertures. The random dots were mapped on a plane that translates in a fronto-parallel plane (uniform 2D translation) or in depth (3D, corresponding to a non-uniform projected velocity field, either expanding or contracting). The grating was either moving rigidly with the dots or in the opposite direction. Subjects' responses show that the direction of line grating movement was reliably influenced only in conditions consistent with rigid motion; where there was a reliable influence, the perceived direction was consistent with the dot motion pattern. This finding points to the existence of a motion-based selection mechanism that operates prior to the disambiguation of the line movement direction. Disambiguation could occur for both uniform and non-uniform velocity fields, even though in the last case none of the individual dots indicated the proper direction in 2D velocity space. Finally, the capture by non-uniform motion patterns was less robust than that by uniform 2D translations, and could be disrupted by manipulations of the shape and size of the apertures. |
| | |
Authors:
|
I Lamouret; V Cornilleau-Pérès; J Droulez |
Related Documents
:
|
10710763 - Dynamic capture of sound motion by light stimuli moving in three-dimensional space. 11412883 - Broad direction bandwidths for complex motion mechanisms. 22419983 - Balance equations can buffer noisy and sustained environmental perturbations of circadi... |
Publication Detail:
|
Type: Journal Article |
Journal Detail:
|
Title: Vision research Volume: 41 ISSN: 0042-6989 ISO Abbreviation: Vision Res. Publication Date: 2001 Aug |
Date Detail:
|
Created Date: 2001-07-12 Completed Date: 2001-08-16 Revised Date: 2004-11-17 |
Medline Journal Info:
|
Nlm Unique ID: 0417402 Medline TA: Vision Res Country: England |
Other Details:
|
Languages: eng Pagination: 2207-19 Citation Subset: IM |
Affiliation:
|
Laboratoire de Physiologie de la Perception et de l'Action, CNRS-Collège de France, 11, place Marcelin Berthelot, 75 005 Paris, France. ivan.lamouret@college-de-france.fr |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adult Depth Perception / physiology Humans Motion Perception / physiology* Pattern Recognition, Visual / physiology* Perceptual Distortion / physiology Psychophysics |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Direction-specific changes of sensitivity after brief apparent motion stimuli.
Next Document: Size-based selection in rapid serial visual presentation.