Sharp targets are detected better against a figure, and blurred targets are detected better against a background.

Cole, Gellatly, and Blurton (2001) have shown that targets presented adjacent to geometric corners are detected more efficiently than targets presented adjacent to straight edges. In six experiments, we examined how this corner enhancement effect is modulated by corner-of-object representations (i.e., corners that define an object's shape) and local base-level corners that occur as a result of, for instance, overlapping the straight edges of two objects. The results show that the corner phenomenon is greater for corners of object representations than for corners that do not define an object's shape. We also examined whether the corner effect persists within the contour boundaries of an object, as well as on the outside. The results showed that a spatial gradient of attention accompanies the corner effect outside the contour boundaries of an object but that processing within an object is uniform, with no corner effect occurring. We discuss these findings in relation to space-based and object-based theories of attention.

Section: Discussionsupporting

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Object and spatial representations in the corner enhancement effect

Cole

Skarratt

Gellatly

2007

“…This explanation also clarifies the finding of Wong and Weisstein (1983) that sharp targets are detected better against a figure and blurred targets are detected better against a background. Sharp targets are detected better against a figure because they are processed by scales that can sharply fuse their features.…”

Section: Better Discrimination Of Figure Than Of Groundmentioning

confidence: 55%

“…Such studies have led to the hypothesis that low spatial frequency, fast channels generate a percept's coarse background, whereas high spatialfrequency, slower channels elaborate the percept's finer figural representations (Breitmeyer & Ganz, 1976;Ginsburg, 1982;Julesz, 1978;Wong & Weisstein, 1983). The present theory shows how this can happen without contradicting such basic properties as the size-disparity correlation and the fact that an object's image on the retina increases in size as it approaches an observer.…”

Section: Multiscale Interactions Of the CC Loopmentioning

confidence: 99%

3-D vision and figure-ground separation by visual cortex

Grossberg

1994

420

632

A neural network theory of three-dimensional (3-D)vision, called FACADE theory, is described. The theory proposes a solution of the classical figure-ground problem for biological vision. It does so by suggesting how boundary representations and surface representations are formed within a boundary contour system (BCS) and a feature contour system (FCS). The BCS and FCS interact reciprocally to form 3-D boundary and surface representations that are mutually consistent. Their interactions generate 3-D percepts wherein occluding and occluded object parts are separated, completed, and grouped. The theory clarifies how preattentive processes of 3-D perception and figure-ground separation interact reciprocally with attentive processes of spatial localization, object recognition, and visual search. A new theory of stereopsis is proposed that predicts how cells sensitive to multiple spatial frequencies, disparities, and orientations are combined by contextsensitive filtering, competition, and cooperation to form coherent BCS boundary segmentations. Several factors contribute to figure-ground pop-out, including: boundary contrast between spatially contiguous boundaries, whether due to scenic differences in luminance, color, spatial frequency, or disparity; partially ordered interactions from larger spatial scales and disparities to smaller scales and disparities; and surface filling-in restricted to regions surrounded by a connected boundary. Phenomena such as 3-D pop-out from a 2-D picture, Da Vinci stereopsis, 3-D neon color spreading, completion of partially occluded objects, and figure-ground reversals are analyzed. The BCS and FCS subsystems model aspects of how the two parvocellular cortical processing streams that join the lateral geniculate nucleus to prestriate cortical area V4 interact to generate a multiplexed representation of Form-And-Color-And-DEpth, or FACADE, within area V4. Area V4 is suggested to support figure-ground separation and to interact with cortical mechanisms of spatial attention, attentive object learning, and visual search. Adaptive resonance theory (ART) mechanisms model aspects of how prestriate visual cortex interacts reciprocally with a visual object recognition system in inferotemporal (IT)

“…Organizational influences on the spatial frequency response of the visual system also support this view. The detection of high spatial frequency targets has been found to be enhanced in perceived figure relative to perceived ground regions, whereas for low spatial frequency targets, the results have been the reverse (Wong & Weisstein, 1983). Detection of contour discontinuity, a task requiring detailed (high spatial frequency) information, has also been found to be better when the contour is part of a figure than when it is part of a ground (Weitzman, 1963).…”

Section: Discussionmentioning

confidence: 77%

A spatial frequency effect on perceived depth

Brown

Weisstein

1988

Self Cite

We report a spatial frequency influence on perceptual organization. If regions filled with relatively higher spatial frequency sinusoidal gratings are adjacent to regions containing relatively lower spatial frequency gratings, the regions with the higher frequency will appear closer in depth than those containing the lower frequency. This depth effect is evident even when conflicting stereo information is present.Previous work has revealed an intriguing phenomenon in apparent depth (Brown & Weisstein, 1985). If alternate "bars" (horizontal rectangles) in a visual field are filled with sinusoidal gratings that differ in spatial frequency, the regions with the relatively higher frequency grating will appear closer in depth than the regions with the relatively lower frequency grating ( Figure I). This appearance of depth increases as the octave separation between the high-and low-frequency gratings increases. The effect is consistent, and, when considered in terms of relative size and detail perspective (Kaufman, 1974), it is also unexpected. According to these monocular depth cues, the larger bars of the lower frequency filled regions might be expected to provide depth/distance information indicating that they are nearer in depth than the narrower bars of the higher frequency filled regions.There is increasing evidence of a link between the perception of depth and the sensitivity of the visual system to spatial frequency information. For example, Pentland (1985) has shown that the more an occluded object is blurred (high-spatial-frequency information being attenuated) the more the occluding object appears to stand out in apparent depth in front of it. Other related studies have found spatial frequency influences on figure-ground perception (Klymenko & Weisstein, 1986;Wong & Weisstein, 1985). Alternate regions of figure-ground reversible configurations were filled with sinusoidal gratings of differing spatial frequency. Whether the configuration was Rubin's (1921Rubin's ( /1958 containing the relatively lower spatial frequency. The larger the octave separation in spatial frequency, the more likely the higher frequency filled regions were organized as figure. While these studies did not directly address the perceived depth created within their stimuli, the implicit depth relations accompanying a figure-ground segregation specified the figure regions (and thus the relatively higher spatial frequency filled regions) closer in depth a greater percentage of the time.Most pertinent to our present findings are studies that directly examined the effect of spatial frequency on the perception of depth (Frisby & Mayhew, 1978;Schor & Howarth, 1986). Frisby and Mayhew (1978) used stimuli consisting of two-dimensional, spatial frequency filtered, rivalrous-textured, random-dot stereograms. They found that a central square centered at 10 cycles per degree (cpd) appeared closer in depth than its surround centered at 2.5 cpd, despite contrary stereo information, Two factors may have contributed to their results. Having a smaller...