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UID:20250920T112554EDT-2412DWFHKe@132.216.98.100
DTSTAMP:20250920T152554Z
DESCRIPTION:Humans are sensitive to modulations of luminance (first order)
 \nand texture contrast (second order) and there is a body of evidence\nto 
 suggest that detection of these stimulus types is separate even\nthough th
 e two cues do interact in early vision. Models for the\ndetection of secon
 d-order stimuli propose considerable extra neural\nhardware on top of that
  required for first-order vision. Such\nexpense suggests that second-order
  cues should provide useful\ninformation in the natural environment and ex
 ploration of natural\nscenes suggests that first- and second-order signals
  are indeed\nuncorrelated over an ensemble of images using a signed metric
 \n(Schofield\, Perception\, 29\,\n1071 – 1086\, 2000). However\, they are 
 correlated\non an unsigned metric suggesting that they frequently occur\nt
 ogether (Johnson & Baker\, JOSA-A\, 21\, 913–925\,\n2004). Further\, first
 - and second-order cues tend to be positively\ncorrelated when textured su
 rfaces are shaded or fall into cast\nshadows. This suggests that the relat
 ionship between the two cues\ntypes might be used to determine the origin 
 of luminance changes in\nterms of illumination versus reflectance changes.
  Thus second-order\nvision could enable layer segmentation\; the separatio
 n of\nillumination and reflectance. I will present experimental data and\n
 computational models in support of this idea and show how\nsecond-order cu
 es can be combined with other cues to perform layer\nsegmentation in a com
 puter vision application.\n \n
DTSTART:20110325T170000Z
DTEND:20110325T180000Z
SUMMARY:Seminar by Andrew Schofield\, University of Birmingham\, 'What is s
 econd-order vision for?'
URL:/channels/event/seminar-andrew-schofield-universit
 y-birmingham-what-second-order-vision-173065
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