Realization of two-dimensional digital filters with powers-of-two coefficients

Abstract

This paper aims at the simplification of operation and the reduction of hardware complexity and presents the construction of the two-dimensional digital filter using powers-of-two coefficients. The proposed two-dimensional digital filter is composed of a cascade connection of one-dimensional digital filters with different frequency axis. The digital filter is structured as a cascade connection of the stopband-forming filter and the passband-compensating filter. The stopband-forming filter is composed of the cascade connection of recursive running sum (RRS), and the passband-compensating filter is constructed as a linear-phase FIR or IIR type. The proposed method is especially effective for constructing a narrowband LPF. The zero coefficient sensitivity is realized by eliminating the multiplier. Another point is that the elliptic or polygonal two- dimensional filter can be approximated, which has been impossible by McClellan transform. The proposed method can realize more general two-dimensional digital filters with a smaller hardware complexity, thereby eliminating the multiplier. Finally, it is verified by design examples that the hardware complexity is reduced in the proposed two-dimensional digital filter, compared to the traditional method.