Design of a class of maximally-flat spatial filters

In this paper, we present a design technique for a particular class of spatial linear filters, with a zero-phase and maximally-flat frequency response. The design is achieved in the frequency domain and is based on prototype filters obtained using the maximally-flat approximation. The proposed design method is enough general and is valid for several types of filters. Here we present the design of 2D low-pass filters with circular symmetry and also orientation-selective filters with elliptic symmetry. The designed filters are realized using CNNs, nevertheless they can be also regarded as discrete spatial filters, which can be implemented digitally using currently available methods. Simulation results on a grayscale image are given, showing their filtering capabilities