Delta operator based 2-D filters: symmetry, stability, and design

Properties of delta operator based 2-D transfer functions and their application for the design of 2-D filters are considered. Conditions on complex coefficient transfer functions that arise due to stability and various symmetries in frequency responses are listed. Efficient procedures for the design of 2-D filters that utilize these symmetry and stability conditions are presented. An example is presented to illustrate this design procedure. The example also shows that the delta operator based design requires only 2 significant digits of precision to maintain accurate frequency response while the z-domain design needs 5 significant digits.