Modified stabilisation technique for 2-dimensional recursive digital filter design

A new stabilisation procedure is presented, based on the spectral factorisation in the cepstrum domain. Pistor´s stability criterion is used for the stability of the resulting filter. It is shown that any unstable causal 2-dimensional filter function can be decomposed into stable filters that recurse in a halfplane. The new procedure has been compared with the planar least-squares inverse of Shanks and the discrete Hilbert transform of Read and Treitel. It has been found that the present stabilisation technique has a better frequency response approximation than the existing ones. The method is therefore an attractive alternative to the least-squares procedure and the discrete Hilbert transform method.