2D ZERO-PHASE FIR FILTER DESIGN WITH NONUNIFORM FREQUENCY SAMPLING

Abstract

In this paper, nonuniform frequency sampling techniques used in the design of two-dimensional zero-phase FIR filters are proposed and investigated. The design problem is treated as a bivariate interpolation problem with unevenly spaced data. The main idea is to select (find) sampling locations in the (ω1, ω2) frequency plane and corresponding sample values Hd(ω1k, ω2k) of the desired filter frequency response such that the designed filter performance is high. Although the filters designed with the proposed techniques are not optimal, the methods are conceptually simple and produce filters with high degree of shape regularity and approximation error comparable and sometimes even smaller than the "conventional" 2D FIR filter design methods.