An efficient algorithm for characteristic polynomial of 2-D state-space structures

For a class of 2-D digital filters realized by a 2-D state-space structure, two different methods for computing the coefficients of their characteristic polynomial are introduced. The relative efficiencies of these methods are compared with that of the conventional method. An efficient method is then chosen which computes the coefficients with a minimum number of multiplications. The effectiveness of this method has been examined on a numerical example.