Open AccessThe aperture problem in contoured stimuli
Author(s) -
David Kane,
Peter J. Bex,
Steven C. Dakin
Publication year - 2009
Publication title -
journal of vision
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.126
H-Index - 113
ISSN - 1534-7362
DOI - 10.1167/9.10.13
Subject(s) - aperture (computer memory) , optics , stimulus (psychology) , spatial frequency , ambiguity , artificial intelligence , computer science , mathematics , computer vision , physics , acoustics , psychology , cognitive psychology , programming language
A moving object elicits responses from V1 neurons tuned to a broad range of locations, directions, and spatiotemporal frequencies. Global pooling of such signals can overcome their intrinsic ambiguity in relation to the object's direction/speed (the "aperture problem"); here we examine the role of low-spatial frequencies (SF) and second-order statistics in this process. Subjects made a 2AFC fine direction-discrimination judgement of 'naturally' contoured stimuli viewed rigidly translating behind a series of small circular apertures. This configuration allowed us to manipulate the scene by randomly switching which portion of the stimulus was presented behind each aperture or by occluding certain spatial frequency bands. We report that global motion integration is (a) largely insensitive to the second-order statistics of such stimuli and (b) is rigidly broadband even in the presence of a disrupted low SF component.