Extracting Object Contours Including Subjective Contours Against Complex Background. Is a Zebra Visible?

Completion of Visible Contours

Extracting contours by perceptual grouping

A new contour extraction method is described in this paper. It is based on organization of the image data using perceptual grouping rules. and is therefore largely domain independent. The first step is to form an intermediate line segment representation of the contours by grouping edge points in paraBe and at different re~so~ution.s, The main feature of the hne .segn~ent extra~ti[~n process is ...

Shape Encoding and Subjective Contours

Ullman proposes that subjective contc,.us consist of two circles which meet smoothly and which arc tangential to the contrast boundaries from which they originate. The foim of the solution derives from a number of premises, one of which Ullman calls “the locality hypothesis”. ‘Ihis is “based in part on cxpcrimcntal obscrvntions, and partly on a theoretical consideration” ([I 51 ~2). ‘I’hc “cxpc...

Subjective contours and apparent depth.

Schumann (1904) investigated the physical parameters which affect the perception of contour. He reported that for a contour to be perceived the prerequisite was some relatively abrupt local change in brightness or color. In the course of these investigations, however, he noted that under certain favorable conditions contours could be made to appear in areas of the visual field where the physica...

Extracting Meaningful Slopes from Terrain Contours

Good quality terrain models are becoming more and more important, as applications such as runoff modelling are being developed that demand better surface orientation information than is available from traditional interpolation techniques. A consequence is that poor-quality elevation grids must be massaged before they provide useable runoff models. Rather than using direct data acquisition, this...