Premium
Spatial integration of signal information in Gabor stimuli
Author(s) -
Syväjärvi Antti,
Näänen Risto,
Rovamo Jyrki
Publication year - 1999
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1046/j.1475-1313.1999.00415.x
Subject(s) - contrast (vision) , spatial frequency , weighting , signal (programming language) , gaussian , optics , gabor transform , grating , computer science , mathematics , pattern recognition (psychology) , artificial intelligence , computer vision , physics , acoustics , time–frequency analysis , filter (signal processing) , quantum mechanics , programming language
Summary We studied spatial integration of Gaussian weighted cosine gratings (Gabor gratings) in contrast detection by using a two‐alternative forced‐choice method. The Gabor gratings, which were either complete or sharply truncated to a square shape, were presented either in the presence or absence of static noise. Contrast thresholds were determined for different truncation areas and different widths of the two‐dimensional Gaussian weighting function. Contrast detection performance was found to depend only on the effective spatial spread of the stimuli. The spatial spread is a physical description of signal area, which takes into account the spatial inhomogeneity of the signal. The highest detection efficiencies were obtained when the spatial spread was small independently of whether the stimuli were sharply truncated or complete smooth Gabor gratings. The results show that the contrast detection mechanism takes into account the shape of the signal window and does not collect information outside the area of the signal.