AN ORTHOGONAL APPROACH TO THE SPATIAL-DOMAIN DESIGN OF 2-D RECURSIVE AND NONRECURSIVE NONLINEAR FILTERS

An orthogonal algorithm is used to design 2-D nonlinear filters which have spatial-domain representations as subsets of the general second-o rder 2-D nonlinear polynomial. This paper, using these polynomial mode ls, introduces a noniterative spatial-domain design technique to find the coefficients of the nonlinear filters. The method makes use of the Minimum Mean-Square Error (MMSE) criterion and allows for optimally r educing the number of non-zero coefficients in the filter model to mee t a specified mean-square error. Furthermore, it guarantees a unique s et of filter coefficients as the solution for a given filter structure . The algorithm is used to design recursive and nonrecursive nonlinear filters and it is shown that by introducing the recursive part, the f ilter performance is significantly improved.