A New approach to simplification of contours

ABSTRACT A NEW APPROACH TO SIMPLIFICATION OF CONTOURS Skeleton lines (i.e. ridge and drainage lines) were supposed to be signs of characteristic parts of contours and used as tools in determination of characteristic points of contours. If a point of contour is a point of skeleton line or the nearer end point of a segment of contour crossed by a skeleton line then it was supposed to be a characteristic point of contour. Characteristic points were automatically determined during the process of derivation of skeleton lines from contours in accordance with the method developed by Aumann et. al (1991). It is required that the methods used for generalization of contours especially retain the characteristic parts of contours. However, the applications made with three widely used simplification methods (n. point, distance tolerance and angle tolerance) have shown that the requirement is not more or less satisfied because these methods do not have any criterion for either determination of characteristic points or consideration of the determined characteristic points. In this study the methods mentioned above were reorganized in a way that they consider the determined characteristic points as well. In other words a new simplification criterion was embedded in the methods separately and thus it was guaranteed to retain the characteristic parts of contours. Besides, second degree skeleton lines and second degree characteristic points were derived by extending of skeleton lines. Finally, contours were generalized considering the second degree characteristic points as well, and in this case it was shown that the second degree characteristic parts of contours were retained as well. In other words it was proven that contours could be generalized more faithfully by considering the second degree characteristic points. Key Words: Contours, skeleton lines, constrained Delaunay triangulation, derivation of skeleton lines, generalization, simplification, smoothing tCYfilCSEKÖ?RETİM KURULU DOKÜMANTASYON MERKEZİ vı