Study of elliptically symmetrical two-dimensional digital filters possessing separable denominator transfer functions

Two-dimensional digital filters are being widely used in modern image processing software for various types of analysis. The main objective of this thesis has been to implement two-dimensional filter functions using simple design procedures such that the presence of elliptical symmetry in such designed filters are obtained by parameter modifications. In keeping with the simple design criteria, the two-dimensional filters studied in this thesis have been designed starting from a product of two one dimensional filters. Only IIR Filters have been considered for this purpose due to their flexibility in terms of altering filter parameters to obtain new filters. The filters have been checked for stability before analysis. The design has made use of the fact that varying the feedback factor ' k ' in an IIR filter produces a near-elliptical symmetric response for certain values of ' k 1 ' and ' k 2 ' having specific magnitude ranges. Considerable success has been achieved in obtained near-elliptical symmetry especially among the two-dimensional lowpass filters and also in other types of filters. It has also been found that there exists numerous possibilities to achieve near elliptical symmetry based on parameter modifications (values of k 1 and k 2 ) and magnitude range of the filter under study. (Abstract shortened by UMI.