Design of separable 2-D IIR Filters with approximately linear phase in the passband using genetic algorithm

The paper presents a method for designing approximately linear-phase 2-D IIR filters using LS error criterion. The filter design problem is transformed into an equivalent optimization problem. The stability constraints are explicitly included into this problem. A hybrid approach for solving the considered optimization problem is proposed. In the first step, a genetic algorithm is applied. The final point from the genetic algorithm is used as the starting point for a local optimization method. The application of the GA ensures that the obtained solution is not trapped at a local minimum. Using a local optimization method in the second step results in improving the speed of convergence. Two design examples are given to illustrate the proposed technique.