Error spectrum shaping in 2-D digital filters

A technique for reducing the output noise variance in two-dimensional (2-D) recursive digital filters is developed by means of the high-order error feedback consisting of a 2-D FIR digital filter. First, the optimal error feedback coefficients in the 2-D FIR digital filter are derived. Next, the suboptimal error feedback coefficients are found in which the coefficients in the 2-D FIR digital filter are constrained to be symmetric. Finally, a numerical example is given to illustrate the utility of the proposed technique