Perceptual economy and the impression of visual depth

Vickers, Douglas

doi:10.3758/bf03205760

Cited by 22 publications

(16 citation statements)

References 19 publications

(17 reference statements)

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“…The specific adaptive features of minimum tendencies also are not specified by an evolutionary approach as such, and they must be investigated for each type of sensory system in relation to its environment. Similar remarks apply to the programmatic suggestion that the minimum principle is an acquired strategy of cognitive economy (Vickers, 1971).…”

Section: Competing Explanatory Foundations For the Minimum Tendencymentioning

confidence: 84%

The status of the minimum principle in the theoretical analysis of visual perception.

Hatfield¹,

Epstein²

1985

Psychological Bulletin

149

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Section: Competing Explanatory Foundations For the Minimum Tendencymentioning

confidence: 84%

The status of the minimum principle in the theoretical analysis of visual perception.

Hatfield¹,

Epstein²

1985

Psychological Bulletin

149

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“…Instead, it has dealt with the phenomenal impression of three-dimensionality of receding surfaces (see, e.g., Attneave & Olson, 1966;Braunstein,. 1976;Marr, 1982;Stevens, 1981a;Vickers, 1971;Witkin, 1981). It is this literature, we believe, that is a more appropriate starting point in trying to answer the questions posed at the beginning of this article-how we perceive surfaces, what information is available, and what information we use.…”

Section: Discussionmentioning

confidence: 99%

Three gradients and the perception of flat and curved surfaces.

Cutting

Millard²

1984

Journal of Experimental Psychology: General

200

143

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SUMMARYResearchers of visual perception have long been interested in surfaces. Most psychologists have been interested in the perceived slant of a surface and in the gradients that purportedly specify it. Slant is the angle between the line of sight and the tangent to the planar surface at any point, also called the surface normal. Gradients are the sources of information that grade, or change, with visual angle as one looks from one's feet upward to the horizon. The present article explores three gradients-perspective, compression, and densityand the phenomenal impression of flat and curved surfaces. The perspective gradient is measured at right angles to the axis of tilt at any point in the optic array; that is, when looking down a hallway at the tiles of a floor receding in the distance, perspective is measured by the x-axis width of each tile projected on the image plane orthogonal to the line of sight. The compression gradient is the ratio of y/x axis measures on the projected plane. The density gradient is measured by the number of tiles per unit solid visual angle. For flat surfaces and many others, perspective and compression gradients decrease with distance, and the density gradient increases. We discuss the manner in which these gradients change for various types of surfaces. Each gradient is founded on a different assumption about textures on the surfaces around us.In Experiment 1, viewers assessed the three-dimensional character of projections of flat and curved surfaces receding in the distance. They made pairwise judgments of preference and of dissimilarity among eight stimuli in each of four sets. The presence of each gradient was manipulated orthogonally such that each stimulus had zero, one, two, or three gradients appropriate for either a flat surface or a curved surface. Judgments were made for surfaces with both regularly shaped and irregularly shaped textures scattered on them. All viewer assessments were then scaled in one dimension. Multiple correlation and regression on the scale values revealed that greater than 98% of the variance in scale values was accounted for by the gradients. For the flat surfaces a mean of 65% of the variance was accounted for by the perspective gradient, 28% by the density gradient, and 6% by the compression gradient. For curved surfaces, on the other hand, a mean of 96% of the variance was accounted for by the compression gradient, and less than 2% by either the perspective gradient or the density gradient. There were no differences between results for surfaces with regularly shaped and irregularly shaped textures, demonstrating remarkable tolerance of the visual system for statistical variation.The differential results for the flat and curved surfaces suggest independent channels of information that are available in the optic array to observers for their use at different times and in different situations. We argue that perspective information seems to be most important for flatness judgments because that information is a component of an invariant available to'...

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“…Attneave and Olson found that when convergence and compression conflicted, the judged direction of slant was determined by the direction of convergence. Cutting and Millard (1984) summarize research on slant perception, noting that' 'it is generally known that the perspective gradient is more potent than compression (e.g., Rosinski & Levine, 1976;Vickers, 1971) for the perception of a flat surface receding in the distance" (p. 201). Thus, the parallel texture (splay angle) appears to dominate for both judgments of altitude (Wolpert et al, 1983) and judgments of slant.…”

Section: The Second Term In Equation 2 [Y;!z) Cosmentioning

confidence: 99%

Active regulation of altitude as a function of optical texture

Flach

Hagen

Larish

1992

Perception & Psychophysics

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Two empirical studies are reported that examine active regulation of altitude as a function of the type of ground texture. Three ground textures were examined: lines perpendicular to the direction of motion, lines parallel to the direction of motion, and the combination (i.e., square or checkerboard texture). Although subjects only controlled altitude, disturbances were introduced on three axes: vertical, lateral, and fore-aft. The results show a clear advantage for texture parallel to the direction of motion. However, in considering these results in the context of previous research on altitude control, the argument is made that there is no compelling evidence that suggests either parallel (splay) or perpendicular (density) texture is privileged with regard to altitude control. Rather, the most effective display for altitude control will be the one that best isolates the optical activity associated with changing altitude from the optical activity arising from other sources of disturbance (such as forward locomotion). Such a display will make it easier for the observer to distinguish and respond specifically to the disturbances of altitude.Gibson, Glum, and Rosenblatt (1955) argued that "motion perspective" provided "a basis for the judgments required for the control of locomotion" (p. 385). Motion perspective refers to the flow of texture elements within the optic array of a moving observer. The research reported here focused on one aspect of the visual control of locomotion-regulation of altitude. Two sources of information within the optic array were examined: optical splay angle and global optical density (or optical depression angle). We begin by presenting an analysis of the optical geometry to show the linkage between altitude and optical splay angle and optical depression angle. Next, we review previous research where there is currently debate about the relative efficacy of these two sources of information. We then present two empirical studies that examined these two sources of information in an altituderegulation task. Finally, we attempt to integrate our results with those from previous studies and discuss the theoretical and practical implications. OPTICAL ANALYSISThe term optical splay was introduced by Warren (1982). Warren cites Biggs (1966), who noted that when an observer maintains a constant distance to a line on the ground plane (e.g., the curb of the road), despite the shifting optical positions of the individual points composing the line, the optical position of the line was invariant. For a straight line parallel to the direction of motion, the invariant optical position can be defined in terms of the angle at the vanishing point formed by the line and a second line perpendicular to the horizon along the ground trace of forward motion, as shown in Figure 1. Thus, it can be defined by the equation:where S is the splay angle, Y I is the lateral displacement of the line from the perpendicular, and z is the altitude (eyeheight) of the observer. This equation describes the projection onto the f...

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Perceptual economy and the impression of visual depth

Cited by 22 publications

References 19 publications

The status of the minimum principle in the theoretical analysis of visual perception.

The status of the minimum principle in the theoretical analysis of visual perception.

Three gradients and the perception of flat and curved surfaces.

Active regulation of altitude as a function of optical texture

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