Document Detail


Detecting a trajectory embedded in random-direction motion noise.
MedLine Citation:
PMID:  7839611     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Human observers can easily detect a signal dot moving, in apparent motion, on a trajectory embedded in a background of random-direction motion noise. A high detection rate is possible even though the spatial and temporal characteristics (step size and frame rate) of the signal are identical to the noise, making the signal indistinguishable from the noise on the basis of a single pair of frames. The success rate for detecting the signal dot was as high as 90% when the probability of mismatch from frame-to-frame, based on nearest-neighbor matching, was 0.3. Control experiments showed that trajectory detection is not based on detecting a "string" of collinear dots, i.e. a stationary position cue. Nor is a trajectory detected because it produces stronger signals in single independent motion detectors. For one thing, trajectory detection improves with increases in duration, up to 250-400 msec, a duration longer than the integration typically associated with a single motion detector. For another, the signal dot need not travel in a straight line to be detectable. The signal dot was as reliably detected when it changed its direction a small amount (about 30 deg or less) each frame. Consistent with this, circular paths of sufficiently low curvature were as detectable as straight trajectories. Our data suggest that trajectory motion is highly detectable in motion noise because the component local motion signals are enhanced when motion detectors with similar directional tuning are stimulated in a sequence along their preferred direction.
Authors:
S N Watamaniuk; S P McKee; N M Grzywacz
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Vision research     Volume:  35     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  1995 Jan 
Date Detail:
Created Date:  1995-02-24     Completed Date:  1995-02-24     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  65-77     Citation Subset:  IM; S    
Affiliation:
Smith-Kettlewell Eye Research Institute, San Francisco, CA 94115.
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MeSH Terms
Descriptor/Qualifier:
Cues
Discrimination (Psychology) / physiology
Female
Fixation, Ocular
Humans
Male
Motion Perception / physiology*
Optical Illusions / physiology
Pattern Recognition, Visual / physiology
Time Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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