Fuzzy epsilon filters for removal of thermal and speckle noise from gray-scale images
Horst J. Bessai · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1994
This paper develops constructions of filters for semi-automatic enhancement of still images. It emphasizes the joint application of linear and nonlinear filtering techniques. The decision which filter type is to be activated predominantly depends on perceptual criteria. These means of judging are readily described in terms of linguistic variables, i.e., the user is relieved from the tedious task of evaluating noise statistics. The decision process itself is supported by standard fuzzy reasoning techniques and corrected updates of the crisp outputs are available on a user-defined frame-by-frame or window-by-window basis. Thus, both handling of the filter tools and the individual filtering depth (gain, bandwidth, etc.) are controlled by a common rule base. Experiments with noisy grayscale images demonstrate that compared to non-joint methods, the proposed solution results in acceptable scene interpretation and clear identification of originally concealed objects.