Design of 2-D recursive filters with separable denominator transfer functions

The design of 2-D recursive filters with separable denominator transfer functions from the impulse response of a prototype filter is performed in two steps. First the poles of the transfer function of the recursive filter are found using an LMS criterion through an iterative scheme. According to the same criterion, the coefficients of the numerator may then be found by solving linear systems. For prototype filters with real transfer functions, the numerator can also be adjusted by minimizing a Chebyshev criterion.