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SUMMARY:Perceptual Organization of Shape - Dr James Elder\, York Universit
 y\, Toronto
DTSTART:20150417T120000Z
DTEND:20150417T130000Z
UID:TALK58485@talks.cam.ac.uk
CONTACT:John Mollon
DESCRIPTION:Humans are very good at rapidly detecting salient natural shap
 es such as animals in complex scenes.  This suggests that our visual syste
 m is finely tuned to the statistics of natural shape\, and this is borne o
 ut by recent evidence for efficient coding of local shape information.    
 In computational models the prevailing view has been that these local regu
 larities drive the perceptual organization of global shape in feed-forward
  fashion.  However\, feed-forward computer vision algorithms fall well bel
 ow human levels of performance\, and recent results suggest that perceptua
 l organization is also drive by global cues.   This suggests a recurrent a
 rchitecture in which higher areas of the object pathway generate shape hyp
 otheses that condition grouping processes in early visual areas.   As a ca
 ndidate generative model for shape coding\, I will explore a framework in 
 which shape is progressively represented as a sequence of deformations cal
 led formlets.   I will compare this formlet representation with alternativ
 e theories in terms of accuracy in completing fragmented shape hypotheses 
 that may be generated by the early visual system\, and in terms of capturi
 ng the shape information required for recognition.
LOCATION:Kenneth Craik Room\, Craik-Marshall Building\, Downing Site
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