Inconsistent channel bandwidth estimates suggest winner-take-all nonlinearity in second-order vision

Zachary M. Westrick, Christopher A. Henry, Michael S. Landy

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

The processing of texture patterns has been characterized by a model that postulates a first-stage linear filter to highlight a component texture, a pointwise rectification stage to convert contrast for the highlighted texture into mean response strength, followed by a second-stage linear filter to detect the texture-defined pattern. We estimated the spatial-frequency bandwidth of the second-stage filter mediating orientation discrimination of orientation-modulated second-order gratings by measuring threshold elevation in the presence of filtered noise added to the modulation signal. This experiment yielded no evidence for frequency tuning. A second experiment, in which subjects had to detect similar second-order gratings while judging their modulation frequency, produced bandwidth estimates of 1-1.5 octaves, similar to estimated bandwidths of first-order channels. We propose that an additional dominant-response-selection nonlinearity can account for these apparently contradictory results.

Original languageEnglish (US)
Pages (from-to)58-68
Number of pages11
JournalVision Research
Volume81
DOIs
StatePublished - Apr 5 2013
Externally publishedYes

Keywords

  • Second-order vision
  • Texture

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

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