A good-continuation model of some occlusion phenomena

Abstract

Occlusion phenomena raise two questions: (1) When will an occluding and a partly occluded object be seen, as opposed to several nonoverlapping objects? (2) What is seen behind the occluding object? Available theories give no satisfactory description of occlusion data. In our view, this situation is at least partially due to the fact that patterns used in occlusion studies are always regular, whereas it is almost unknown which regularities are actually perceived in occlusion patterns. We have therefore collected a complete set of data for a restricted domain of patterns with minimal regularity. Starting from these data, we have developed a model of the perceptual organization of this class of patterns and tested it in a second experiment. The model is a specification of the Gestalt law of good continuation. It assumes that there is a tendency to describe a pattern by the smallest possible number of contour elements and with the smallest possible changes of direction within and between necessary contour elements. The results fit in well with the predictions of the model. It is further demonstrated that the model also describes the preferred interpretations of many regular patterns, published in other studies.

Local and Global Minima in Visual Completion: Effects of Symmetry and Orientation

“…For the stimuli discussed in this paper, the globally predicted percepts will have the highest degree of symmetry possible. In contrast, several researchers recently have proposed purely local theories of completion or theories in which local processes dominate (1) (eg Boselie 1988;Boselie and Wouterlood 1989;Kellman and Shipley 1991;Takeichi et al 1993;Wouterlood and Boselie 1992). While the details of these theories differ, all local theories emphasize the importance for perceptual completion of the spatial locations at which occlusion occurs.…”

“…For example, in one paradigm, the experimenter presents subjects with pictures of what might be partly occluded objects, and subjects draw or describe any perceived completion (eg Boselie 1988;Boselie and Leeuwenberg 1986;Boselie and Wouterlood 1989;Buffart et al 1981Buffart et al , 1983Davi and Sambin 1992;Dinnerstein and Wertheimer 1957;Kellman and Shipley 1991;Wouterlood and Boselie 1992). There are two limitations to the draw/describe method.…”

Traditional and New Principles of Perceptual Grouping

“…Good continuation is also often invoked in models of interpolation which determine the likelihood of filling in a contour between two segments on either side of an occluder (e.g., Wouterlood & Boselie, 1992). One criterion for interpolation is whether two contours are relatable (Kellman & Shipley, 1991), i.e.…”

Integrating Global and Local Aspects of Visual Occlusion

“…They argued that completion will be such that the background shape is completed with the simplest continuous function between points of occlusion. Wouterlood and Boselie (1992) proposed a theory of visual completion that is completely based on local good continuation. However, their theory is designed to predict completions for a restricted set of shapes, ie shapes in which no regularities occur.…”