The elimination of spikes in the magnitude frequency response of 2-D discrete filters by increasing the stability margin

In the numerical design of two-dimensional (2-D) discrete filters, it is known that spurious spikes can and often do appear in the final optimized 2-D magnitude frequency response. Although such spikes usually have extraordinary narrow bandwidths, they can have large magnitudes and often lead to unsatisfactory spatial response. Two methods are presented to remove these spikes by increasing the stability margin in the regions of the frequency plane where they occur.