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Proceedings Paper

Fast-wavelet compass edge detector
Author(s): D. J. Hebert; HyungJun Kim
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Paper Abstract

As an approach to the wavelet detection of local scale and orientation in 2D images we make use of a well known, computationally efficient triangulation of the image domain and some of its lesser-known properties. We choose wavelets supported by cartesian and quincunx lattice squares, antisymmetric about the diagonal. Computational algorithms are based on properties of the triangulations such as the following: the cells of the triangulation form the leaves of a binary tree and the nodes of a directed graph consisting of a simple cycle; the cells are also identified with blocks of interlaced quadtrees consisting of cartesian and quincunx lattice points which also form the vertices of the cells. Pyramid algorithms based on hierarchical triangular scanning of the pixels and half-wavelet-supporting triangles provide efficient encoding and decoding based on local triangle data and stacks. As examples we introduce a Haar wavelet which detects diagonals of squares and we construct a triangular version of the TS wavelet transform which has been recently proposed as an efficient approach to lossless and lossy image compression. We render an edge-enhanced image by reconstruction from significant coefficients of edge- detecting wavelets.

Paper Details

Date Published: 23 October 1996
PDF: 11 pages
Proc. SPIE 2825, Wavelet Applications in Signal and Image Processing IV, (23 October 1996); doi: 10.1117/12.255254
Show Author Affiliations
D. J. Hebert, Univ. of Pittsburgh (United States)
HyungJun Kim, Univ. of Pittsburgh (United States)

Published in SPIE Proceedings Vol. 2825:
Wavelet Applications in Signal and Image Processing IV
Michael A. Unser; Akram Aldroubi; Andrew F. Laine, Editor(s)

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