On the detection of Gabor signals and discrimination of Gabor textures

Caelli, Terry; Moraglia, Giampaolo

doi:10.1016/0042-6989(85)90173-7

Cited by 55 publications

(19 citation statements)

References 16 publications

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“…It is also possible that the orientation boundary will have no effects, given highly practiced observers who may be able to ignore the nontarget cue. Yetanother possibility is that the nontarget cue will act only as some kind of mask, worsening performance whenever it is strong enough to have any effect, as suggested by Caelli and Moraglia (1985).…”

Section: Experiments 1 Effects Of a Strong Orientation Boundary On Thementioning

confidence: 99%

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Interactions between coincident and orthogonal cues to texture boundaries

Phillips

Craven

2000

Perception & Psychophysics

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Arrays with horizontal or vertical texture boundaries formed by element orientation and length cues were displayed, and the texture boundary formed by one cue was specified as the target. The boundaries formed by the two cues were coincident on some trials and orthogonal on others. Observers' accuracy in reporting the orientation of the target boundary was improved by a coincident nontarget boundary and was worsened by an orthogonal one. Conditional mutual information measures are used to show how effects due to contextual modulation can be distinguished from effects due to additive combination of the cues. The results of five experiments are interpreted as evidence that the transmission of information about specific texture boundary cues is modulated by task context but not by a coincident or orthogonal boundary in another cue. Wetherefore distinguish between the effects of "context, " as shown by the effects of any variable not called the target, and "modulatory contextual effects," as shown by the effects of one variable on the transmission of information specifically about another.To process and learn about sensory input, it is necessary to organize it into much smaller subsets that distinguish figures from ground. Texture boundaries are common in natural images, and they play an important role in figural grouping. Psychophysical evidence suggests that feature gradients are computed simultaneously in many distinct feature maps. Minimally, this involves two stages of'filtering for each texture feature. The first detects the features (e.g., Gabor-like elements at a range of orientations and spatial scales), and the second computes the rate ofchange of feature activity across two-dimensional (2-D) spatial position (e.g

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Section: Experiments 1 Effects Of a Strong Orientation Boundary On Thementioning

confidence: 99%

“…Caelli and Moraglia (1985) studied the perception of textures composed of 8 X 8 Gabor patches. The task was to detect a square central 4 X 4 patch distinguished from the surround by the orientation of the patches, their spatial frequency, or both.…”

mentioning

confidence: 99%

Interactions between coincident and orthogonal cues to texture boundaries

Phillips

Craven

2000

Perception & Psychophysics

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“…The most global feature analyzer that could be employed would be one in which the analyzer exactly matched the luminance profile ofthe target. Such a template-matching model (see, e.g., Burgess & Ghaudeharian, 1984;Caelli & Moraglia, 1985, 1986) includes all the local features. To evaluate the performance of such a pattern-matching device (see the Appendix, section 2, for a mathematical formulation of the model), we assumed an observer who had complete knowledge ofthe luminance profiles of both target and foil but did not know in which of four positions the target and/or the foil would occur.…”

Section: Phase Encoding Local Contrast Spatial Features and Pattermentioning

confidence: 99%

Binocular vision enhances phase discrimination by filtering the background

Schneider

Moraglia

Speranza

1999

Perception & Psychophysics

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Previous studies have shown that the detectability of a noise-masked target can be enhanced under stereoscopic viewing when the target's interocular disparity differs from that of the noise. This enhanced detectability can be accounted for by a model postulating that the binocular system linearly sums the left-eye and right-eye views of a visual scene. This model also predicts enhanced phase discrimination under specifiable interocular disparities of target and noise. Two experiments were conducted in which subjects were asked to discriminate between two luminance patterns (target and foil) that differed only in phase. The target patterns were constructed by summating two vertical sinusoidal gratings in which the phase difference between the higher and the lower spatial frequency gratings was 45°. The foils contained the same two component frequencies, with a phase difference of -45°. Thus, targets and foils were mirror images of one another. The ability of subjects to discriminate between these stereoscopically viewed mirror-imagepatterns was investigated under two sets of interocular disparities: those that, according to our model, would unmask one or both spatial frequency components, and those that would leave both components masked by the noise. Phase discrimination was enhanced only when both component frequencies of the target lind foil were unmasked. The implications of these findings . for template-matching and phase-discrimination models of pattern discrimination are considered.

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“…Sensitivity in orientation appears to be about k 30" [Blake and Holopigan 1985;Daugman 19841. The width of the spatial frequency band selected by a detector may be a size change by a factor of ten [Wilson and Bergen 19791 or a factor of four [Daugman 19841, and the number of frequency channels has been variously estimated as between four and ten [Caelli and Moraglia 1985;Harvey and Gervais 1981;Wilson and Bergen 1979]. However, higher discrimination resolutions are achieved by the neural differencing of the outputs of broadly tuned detectors, much as fine color discrimination is achieved neurally by differencing of the outputs of the cone receptors.…”

Section: Orientation and Sizementioning

confidence: 99%

“…In human neural receptive fields, the window and cosine components tend to be coupled so that Iow-fi-equency cosine components have large windows and high-frequency components have small windows. Caelli and Moraglia [1985] did a study to assess the ratio of window width to spatial frequency of the grating component. The window of (l)-(3) is centered at the origin and is circular in outline.…”

Section: Gabor Functionsmentioning

confidence: 99%

Using visual texture for information display

Ware

Knight

1995

ACM Trans. Graph.

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Resultsfrom vision researchare appliedto the synthesis of visual texture for the purposes of information display. The literature surveyed suggests that the human visual system processes spatial information by means of parallel arrays of neurons that can be modeled by Gabor functions. Based on tbe Gabor model, it is argued that tbe fundamental dimensions of texture for human perception are orientation, size ( 1/frequency), and contrast, It is shown that there are a number of trade-offs in the density with which information can be displayed using texture. Two of these are (1) a trade-off between tbe size of tbe texture elements and tbe precision with which the location can be specified, and (2) tbe precision with which texture orientation can be specified and the precision with which texture size can be specified. Two algontbms for generating texture are included.

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On the detection of Gabor signals and discrimination of Gabor textures

Cited by 55 publications

References 16 publications

Interactions between coincident and orthogonal cues to texture boundaries

Interactions between coincident and orthogonal cues to texture boundaries

Binocular vision enhances phase discrimination by filtering the background

Using visual texture for information display

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