Synthesis of 2-D linear phase digital filters

The synthesis of two-dimensional (2-D) linear-phase digital filters is studied in terms of approximation of 2-D transfer functions. A convergence result is established for the approximation of nonrational 2-D transfer functions under a certain mild frequency domain condition. It is shown that the synthesis of 2-D linear-phase FIR (finite impulse response) digital filters can be transformed into an equivalent approximation for which the convergence condition is satisfied. A 2-D linear-phase IIR (infinite impulse response) digital filter is then synthesized based on an FIR model. Several examples are given to illustrate the synthesis technique.<
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