Design of 2-D quadrantally symmetric IIR digital filter using singular value decomposition and ordered real Schur form

A new technique is presented to design quadrantally symmetric 2-D IIR filters. This technique is based on two steps: first, the 2-D impulse response matrix (Hankel matrix) is decomposed by the SVD (singular value decomposition) to k parallel branches, each branch is composed of two cascaded single-input single-output (SISO) 1-D FIR filters. Second, a truncated model reduction algorithm is applied to the 1-D filters to approximate the N/sub l/-dimensional FIR into n/sub l/-dimensional IIR filters, where. n/sub l/