title: Studies of the perception of incomplete outline images of different sizes.
abstract: The aim of the present work was to assess the range of angular sizes of fragmented images of objects at which perception of the images was scale-independent. Measurements were made of human subjects' recognition thresholds for the shapes of the objects over a wide range of angular sizes (0.19-50 degrees). The experiments used the Gollin test--a method for studying the recognition of fragmented outline images of objects with which the observer is familiar. The results obtained demonstrated that there is a wide range of angular sizes, from 1.0 degrees to 50 degrees, over which the perception thresholds of incomplete outline images do not change with changes in size, along with a narrow range of stimulus sizes, 0.19-1.0 degrees, over which there is a significant size dependence. We suggest that the increase in thresholds and the failure to recognize images of small size occur as a result of an increased contribution of sampling noise at the level of the human retina.
authors.affiliation: Visual Physiology Laboratory, I. P. Pavlov Institute of Physiology, Russian Academy of Sciences, 6 Makarov Bank, 199034, St. Petersburg, Russia.
authors.forename: O A
authors.initials: OA
authors.lastname: Vakhrameeva
authors.forename: Yu E
authors.initials: YE
authors.lastname: Shelepin
authors.forename: A Yu
authors.initials: AY
authors.lastname: Mezentsev
authors.forename: S V
authors.initials: SV
authors.lastname: Pronin
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012160:Retina / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology*