| The detectability of geometric structure in rapidly changing optical patterns. | |
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MedLine Citation:
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PMID: 1771135 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Human vision is sensitive to the coherent structure and motion of simple dot patterns undergoing rapid random transformations, even when the component dots are widely separated spatially. A study is reported in which visual sensitivity to translations, rotations, expansions, pure shear, and additive combinations of these transformations was investigated. Observers discriminated between coherent (correlated) movements, in which all the component dots moved simultaneously in corresponding directions and distances, and incoherent (uncorrelated) movements, in which the movements of individual dots were statistically independent. In experiment 1 the accuracy of coherence discrimination was found to be similar for all four of the basic transformations and to increase linearly with the distance of the movements. The discriminability of coherent versus incoherent motion was also found to be similar to the detectability of any motion, suggesting that concurrent movements of individual dots are visually interrelated. In experiments 2 and 3 the visual independence of these four groups of transformations was tested by comparing the accuracy of coherence discrimination of each of the transformations presented alone with that when added to background motions produced by each of the four transformations. Coherence discriminations were less accurate when the target transformation was added to another background transformation, indicating that these transformations are not visually independent. Rotations and expansions, however, were visually independent. In experiment 3 qualitatively similar effects for patterns of several different sizes and dot densities were found. In general, an impressive visual sensitivity to globally coherent structure and motion under several different geometric transformations was observed in these experiments. A basic theoretical issue concerns the local visual mechanisms underlying this sensitivity. |
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Authors:
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J S Lappin; J F Norman; L Mowafy |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Perception Volume: 20 ISSN: 0301-0066 ISO Abbreviation: Perception Publication Date: 1991 |
Date Detail:
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Created Date: 1992-02-27 Completed Date: 1992-02-27 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0372307 Medline TA: Perception Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 513-28 Citation Subset: IM |
Affiliation:
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Department of Psychology, Vanderbilt University, Nashville, TN 37240. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Depth Perception Form Perception* Humans Motion Perception* Space Perception* |
| Grant Support | |
ID/Acronym/Agency:
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EY-05926/EY/NEI NIH HHS; P30EY08126/EY/NEI NIH HHS; T32EY07007/EY/NEI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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