A fuzzy noise-smoothing filter
Harvey B. Mitchell, P. A. Schaefer · International Journal of Intelligent Systems · 2000
The removal of additive noise in digital images is currently a subject of intense interest. Recent research has shown that to be effective the filter should adapt itself to the local structure existing in the image: In regions which have no dominant structure the adaptive filter should act as a linear statistics filter while in regions with a strong or dominant structure the adaptive filter should act as an ordered statistics filter. In the past the adaptive filters worked in a discontinuous mode by switching between a linear statistic filter (used when the local region has no dominant structure) and an ordered statistic filter (used when the local region had a strong structure). In this case, the adaptation mechanism is separate from the noise smoothing algorithm and is usually ad hoc. In this paper we describe a new fuzzy filter in which the adaptation mechanism is no longer ad hoc: instead it is integrated into the noise smoothing algorithm. In addition, the adaptation mechanism works in a continuous mode—changing gradually as we move from a local region with no dominant structure to a local region with a strong dominant structure. © 2000 John Wiley & Sons, Inc.