MODIFIED STABILITY TABLE FOR 2-D DIGITAL-FILTERS

A modified stability table is obtained for checking the stability of 2-D digital filters. In this table, the appropriate entries of the first column are equivalent to the appropriate minors of the Hermitian Schur-Cohn matrix. Thus the positivity of the latter matrix requires the positivity checking of the n-1 entries appropriate entries for one point, and the last entry, which is equivalent to the Schur-Cohn determinant, is to be checked for positivity for all vertical z vertical equals 1. This test is simpler than several others appearing in the literature.