Local and global visual processing

David C. Burr, M. Concetta Morrone, John Ross

Research output: Contribution to journalArticle

Abstract

The fundamental sinusoidal components of a chequerboard pattern are oriented at 45° to the orientation of the chequerboard edges. Removal of one of the fundamental sinusoids (at +45°) creates a useful pattern for studying the mechanisms of visual analysis. Close up, the pattern appears to be oriented +45°, although there is no global energy at that orientation, implying local analysis. At a distance, the perceived diagonality switches to -45° implying access to global information. Measurements show that contrast thresholds for seeing diagonality at +45° follow closely those for detecting the 5th harmonic component of the pattern, over a wide range of spatial frequencies and luminances. Low pass filtering also causes the pattern to be perceived according to its global energy, provided that the cutoff frequency is set to remove the fifth harmonic. We conclude that, at least for this particular stimulus, the visual system performs a local analysis if the fifth harmonic is visible and a global analysis if not.

Original languageEnglish
Pages (from-to)749-757
Number of pages9
JournalVision Research
Volume26
Issue number5
DOIs
Publication statusPublished - 1986

Keywords

  • Chequerboards
  • Global analysis
  • Local analysis
  • Phase

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

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