Improved model reduction procedure for 2-D separable denominator digital systems

An improved procedure is presented for the model reduction of 2-D separable denominator digital systems H(z/sub 1/,z/sub 2/). The proposed procedure is based on modifying the factorization H(z/sub 1/,z/sub 2/)=H/sub 2/(z/sub 2/)H/sub 1/(z/sub 1/) and minimizing an existing frequency error bound developed by Zhou, Li, and Lee (1991). In terms of small actual frequency errors and tight frequency error bounds, this procedure is superior to the existing model reduction methods.