Design of 2-D recursive filters having approximately circularly symmetric variable magnitude characteristics
S. Fallah, V. Ramachandran, Christian S. Gargour · 2003
It is shown that it is possible to obtain variable magnitude characteristics in a two-dimensional recursive digital filter. This is accomplished by the substitution of first-order allpass sections instead of the delay units in the realized filter. Coefficient conditions are obtained so that the various filters are stable and their characteristics are approximately circularly symmetric.>