Proceedings of 1994 28th Asilomar Conference on Signals, Systems and Computers (1994)
Pacific Grove, CA, USA
Oct. 31, 1994 to Nov. 2, 1994
S. Thurnhofer , Dept. of Electr. & Comput. Eng., California Univ., Santa Barbara, CA, USA
S.K. Mitra , Dept. of Electr. & Comput. Eng., California Univ., Santa Barbara, CA, USA
We investigate a class of quadratic Volterra filters, which can be used as computationally efficient edge detectors. Filters from this class are approximately equal to mean-weighted highpass filters, and therefore, they extract fewer edges from dark areas, which is a desirable property for many image enhancement applications. We study the one-dimensional case first and then generalize the results to two dimensions. Since the four-dimensional frequency response yields little insight in the properties of these filters, we also develop a technique for characterizing these filters in a more intuitive way. Using the observation that they map sinusoidal inputs to constant outputs, we employ two-dimensional oriented sinusoids to assess both the frequency characteristics and the degree to which a filter is isotropic, i.e., independent of the input orientation.<
image enhancement, edge detection, feature extraction, filtering theory, high-pass filters, two-dimensional digital filters, Volterra equations, frequency response
S. Thurnhofer and S. Mitra, "Volterra filters for perceptual edge extraction," Proceedings of 1994 28th Asilomar Conference on Signals, Systems and Computers(ACSSC), Pacific Grove, CA, USA, 1995, pp. 736-740.