Catalogo Articoli (Spogli Riviste)
Titolo: HOW BIG IS A GABOR PATCH, AND WHY SHOULD WE CARE
Autore: FREDERICKSEN RE; BEX PJ; VERSTRATEN FAJ;
- UNIV CALIF IRVINE,DEPT COGNIT SCI,SSP-3 IRVINE CA 92697 MCGILL VIS RES MONTREAL PQ H3A 1A1 CANADA UNIV ROCHESTER,CTR VISUAL SCI ROCHESTER NY 14627 HARVARD UNIV,VIS SCI LAB CAMBRIDGE MA 02138
- Titolo Testata:
- Journal of the Optical Society of America. A, Optics, image science,and vision.
pagine: 1 - 12
- CONTRAST GAIN-CONTROL; STRIATE CORTEX; SPATIOTEMPORAL INTEGRATION; SPATIAL SUMMATION; COHERENT MOTION; VISUAL-CORTEX; HUMAN VISION; FIELD; CHANNELS; SIZE;
- Tipo documento:
- Settore Disciplinare:
- Science Citation Index Expanded
- Indirizzi per estratti:
- R.E. Fredericksen et al., "HOW BIG IS A GABOR PATCH, AND WHY SHOULD WE CARE", Journal of the Optical Society of America. A, Optics, image science,and vision., 14(1), 1997, pp. 1-12
Abstract We propose a two-parameter model for the perceived size (spatial extent) of a Gaussian-windowed, drifting sinusoidal luminance pattern (a Gabor patch) based on the simple assumption that perceived size is determined by detection threshold for the sinusoidal carrier. Psychophysical measures of perceived size vary with peak contrast, Gaussian standard deviation, and carrier spatial frequency in a manner predicted by the model. At suprathreshold peak contrasts Gabor perceived size is relatively unaffected by systemic noise but varies in a manner that is consistent with the influence of local contrast gain control. However, at and near threshold, systemic noise plays a major role in determiningperceived size. The data and the model indicate that measures of contrast threshold using Gaussian-windowed stimuli (or any other nonflat contrast window) are determined not just by contrast response of the neurons activated by the stimulus but also by integration of that activation over a noisy, contrast-dependent extent of the stimulus in space and time. Thus, when we wish to measure precisely the influence of spatial and temporal contrast integration on threshold, we cannot do so by combining contrast threshold measures with Gaussian-windowed stimuli. (C) 1997 Optical Society of America.
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Documento generato il 25/11/20 alle ore 03:09:07