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Proceedings Paper

Efficient object contour tracing in a quadtree encoded image
Author(s): G. N. Kumar; Nagaraj Nandhakumar
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Paper Abstract

A new algorithm is presented to extract the chain-code representation of the boundary of a binary image. The quadtree representation of this image acts as the input to the algorithm. This algorithm is more efficient than the previously reported algorithm. The algorithm can trace the boundary according to either eight-connected or four-connected neighborhood definitions without any modification. The boundary is traced in the clock-wise direction with respect to the object. The algorithm is based on the following two observations; (1) Visiting a sequence of four-connected white nodes that lie along the object boundary yields an eight-connected boundary while (2) visiting a sequence of four-connected black nodes that lie along the object boundary yields a four-connected boundary. In other words, tracing the object boundary from outside the object using four-connected neighborhood definition extracts an eight-connected boundary, and tracing the object boundary from within the object using four-connected neighborhood definition extracts a four-connected boundary.

Paper Details

Date Published: 1 March 1991
PDF: 12 pages
Proc. SPIE 1468, Applications of Artificial Intelligence IX, (1 March 1991); doi: 10.1117/12.45527
Show Author Affiliations
G. N. Kumar, Univ. of Virginia (United States)
Nagaraj Nandhakumar, Univ. of Virginia (United States)


Published in SPIE Proceedings Vol. 1468:
Applications of Artificial Intelligence IX
Mohan M. Trivedi, Editor(s)

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