A numerical algorithm for stability testing 2-D recursive digital filters

A simple numerical algorithm is proposed for stability testing of 2-D recursive digital filters. It consists of a Cholesky factorization and a discrete cosine transform program as well as a table method for testing zero locations (with respect to the unit circle) of 1-D polynomials. Under the assumption of no essential singularities of the second kind, the stability of a given 2-D recursive digital filter can be determined in a finite number of steps. An example is worked out to illustrate the technique. It is shown that the algorithm compares very favorably with other stability testing methods