title: The optical-geometrical characteristics and thresholds of perception of fragmented outline figures.
abstract: Measurements were made of the threshold of recognition of cumulatively forming line figures. The threshold value of the outline, expressed in pixels, depended on the length of the outline of the whole unfragmented figure. Relative threshold values were constant, and for the measures of figure fragments used in the present study, averaged 12.5%. A spatial frequency analysis of the test images was performed. Variation of the amplitude-frequency parameters of the spectra of the images of various figures with threshold fragmentation was minimal as compared with the variation of these parameters in figures with subthreshold or suprathreshold levels of fragmentation.
authors.affiliation: Visual Physiology Laboratory and Faculty of Information Technology, I. P. Pavlov Institute of Physiology, Russian Academy of Sciences, 6 Makarov Bank, 199034 St. Petersburg, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Merkul'ev
authors.forename: Yu E
authors.initials: YE
authors.lastname: Shelepin
authors.forename: V N
authors.initials: VN
authors.lastname: Chikhman
authors.forename: S V
authors.initials: SV
authors.lastname: Pronin
authors.forename: N
authors.initials: N
authors.lastname: Foreman
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology*; D013057:Spectrum Analysis / Q000379:methods; D014794:Visual Fields / Q000502:physiology*
references.citation: Perception. 1987;16(4):543-8
references.pmid: 3444734
references.citation: Nature. 1968 Mar 9;217(5132):972-4
references.pmid: 5642857