| Stimulus configuration determines the detectability of motion signals in noise. | |
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MedLine Citation:
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PMID: 10975362 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We measured the detectability of moving signal dots in dynamic noise to determine whether local motion signals are preferentially combined along an axis parallel to the direction of motion. Observers were asked to detect a signal composed of three dots moving in a linear trajectory among dynamic noise dots. The signal dots were collinear and equally spaced in a configuration that was either parallel to or perpendicular to their trajectory. The probability of detecting the signal was measured as a function of noise density, over a range of signal dot spacings from 0.5 degrees to 5.0 degrees. At any given noise density, the signal in the parallel configuration was more detectable than that in the perpendicular configuration. Our four observers could tolerate 1.5-2.5 times more noise in the parallel configuration. This improvement is not due merely to temporal summation between consecutive dots in the parallel trajectory. Temporal summation functions measured on our observers indicate that the benefit from spatial coincidence of the dots lasts for no more than 50 ms, whereas the increased detectability of the parallel configuration is observed up to the largest temporal separations tested (210 ms). These results demonstrate that dots arranged parallel to the signal trajectory are more easily detected than those arranged perpendicularly. Moreover, this enhancement points to the existence of visual mechanisms that preferentially organize motion information parallel to the direction of motion. |
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Authors:
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P Verghese; S P McKee; N M Grzywacz |
Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: Journal of the Optical Society of America. A, Optics, image science, and vision Volume: 17 ISSN: 1084-7529 ISO Abbreviation: J Opt Soc Am A Opt Image Sci Vis Publication Date: 2000 Sep |
Date Detail:
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Created Date: 2000-09-20 Completed Date: 2000-09-20 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 9800943 Medline TA: J Opt Soc Am A Opt Image Sci Vis Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 1525-34 Citation Subset: IM; S |
Affiliation:
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Smith Kettlewell Eye Research Institute, San Francisco, California 94115, USA. preeti@ski.org |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Artifacts* Humans Motion Perception / physiology* Photic Stimulation / methods Probability Time Factors |
| Investigator | |
Investigator/Affiliation:
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P Verghese / Smith-Kettlewell Eye Res Inst, San Francisco, CA |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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