Computational Theories of Visual Perception

Shapley, Robert; Caelli, Terrence; Grossberg, Stephen; Morgan, Michael J.; Rentschler, Ingo

doi:10.1016/b978-0-12-657675-7.50021-1

Cited by 42 publications

(20 citation statements)

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“…Julesz (1981, p. 97) concluded that cortical feature analyzers are "not connected directly to each other" in peripheral vision and interact "only in aggregate." By contrast, research on form vision indicated the existence in the visual cortex of cooperative mechanisms that locally connect feature analyzers (e.g., Carpenter, Grossberg, & Mehanian, 1989;Grossberg & Mingolla, 1985;Lee, Mumford, Romero, & Lamme, 1998;Phillips & Singer, 1997;Shapley, Caelli, Grossberg, Morgan, & Rentschler, 1990).…”

Section: Chapter 1 Introductionmentioning

confidence: 91%

Peripheral vision and pattern recognition: A review

2011

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We summarize the various strands of research on peripheral vision and relate them to theories of form perception. After a historical overview, we describe quantifications of the cortical magnification hypothesis, including an extension of Schwartz's cortical mapping function. The merits of this concept are considered across a wide range of psychophysical tasks, followed by a discussion of its limitations and the need for non-spatial scaling. We also review the eccentricity dependence of other low-level functions including reaction time, temporal resolution, and spatial summation, as well as perimetric methods. A central topic is then the recognition of characters in peripheral vision, both at low and high levels of contrast, and the impact of surrounding contours known as crowding. We demonstrate how Bouma's law, specifying the critical distance for the onset of crowding, can be stated in terms of the retinocortical mapping. The recognition of more complex stimuli, like textures, faces, and scenes, reveals a substantial impact of mid-level vision and cognitive factors. We further consider eccentricity-dependent limitations of learning, both at the level of perceptual learning and pattern category learning. Generic limitations of extrafoveal vision are observed for the latter in categorization tasks involving multiple stimulus classes. Finally, models of peripheral form vision are discussed. We report that peripheral vision is limited with regard to pattern categorization by a distinctly lower representational complexity and processing speed. Taken together, the limitations of cognitive processing in peripheral vision appear to be as significant as those imposed on low-level functions and by way of crowding.

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Section: Chapter 1 Introductionmentioning

confidence: 91%

Peripheral vision and pattern recognition: A review

2011

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“…The half-field pattern ERG studies have confirmed this concept, in that the sum of two halves is slightly greater than the full-field response [3,4]. A satisfactory account of visual perception demands consideration of the visual system as a nonlinear system [5]. The phenomena of masking vernier acuity has led Watt and Morgan [6] to propose a theory requiring a nonlinear transduction, or rectification, of signals in the visual cortex before the positions of vernier lines were calculated.…”

Section: Introductionmentioning

confidence: 91%

Nonlinear Component of the Electroretinogram Recorded from the Posterior Pole of Normal and Highly Myopic Human Eyes

Yoshii

Yanashima²,

Nagasaka³

et al. 2002

Ophthalmic Res

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To extract the nonlinear component of the electroretinogram (ERG) from the posterior pole (pp) of the human ocular fundus and to evaluate the possibility of its clinical application, three types of stimulus modes – double-flash, single-flash, and delayed single-flash stimuli – were produced using a conventional electrophysiological system. A large hexagonal element was presented on a CRT monitor, and ppERGs were recorded from 14 normal eyes and 16 eyes of eight highly myopic patients. The nonlinear component of the ppERG was obtained by subtracting the single-flash ERG and delayed single-flash ERG responses from the double flash ERG response. Three peaks were commonly observed in the nonlinear component of ppERG, all of which were significantly depressed in patients with high myopia. ppERGs that can be obtained using a simple algorithm might be useful in clinical applications.

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“…In a number of different contexts, ranging from X-ray crystallography to perception of human faces, it has been found that objects and people can still be recognised in a Fourier reconstruction despite defective amplitude information (Oppenheim and Lim 1981;Piotrowski and Campbell 1982;Shapley et al 1990). Furthermore, phase information prevails over amplitude.…”

Section: Introductionmentioning

confidence: 98%

The relative importance of local phase and local amplitude in patchwise image reconstruction

1991

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Abstract. Natural images were subjected to patchwise Fourier analysis, and the local amplitude and phase spectra were swapped between different images. When the patches were large relative to the image size, the appearance of the reconstructed image was similar to that of the image from which the phase information had been derived, in agreement with previous reports of phase-dominance in the global Fourier Transform. However, when the patch size was made sufficiently small, the appearance of reconstructed images was dominated by amplitude rather than phase. This was not simply due to the DC component of the amplitude spectrum. Prior low-pass filtering of the images enhanced the dominance of amplitude information in the patchwise transform. We conclude that patchwise-reconstructed images contain two quite distinct kinds of information for the human observer. The first is the positional information ("local sign") of the patches themselves; the second is the textural information within patches, which is dominated by amplitude rather than phase. The reason why the global Fourier Transform is dominated by phase is that in the absence of any other information about local sign, phase is necessary to reconstruct localised features such as edges.

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Computational Theories of Visual Perception

Cited by 42 publications

References 0 publications

Peripheral vision and pattern recognition: A review

Peripheral vision and pattern recognition: A review

Nonlinear Component of the Electroretinogram Recorded from the Posterior Pole of Normal and Highly Myopic Human Eyes

The relative importance of local phase and local amplitude in patchwise image reconstruction

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