Hardware implementation of the median-rational hybrid filters for colour images

A new class of nonlinear Filters called Vector Median Rational Hybrid Filter (VMRHF) [1][2] has been recently introduced and applied to colour image filtering problems. As shown in these papers, hybrid filters exbibit very desirable filtering features which often outperform those of the components of the hybrid filter itself. The VMRHF filter is a two-stage filter, which exploits the features of the vector-median filter and those of the rational operator. The performances of the proposed filter are compared with those of the Vector Median Filter (VMF), described in [3], and of the Directional-Distance Filter (DDF), reported in [4]. In this paper we also present a hardware implementation of the VMRHF which exploits ill all effective way the features and the robustness of both median filters and rational filters. This architecture is suitable for the use in real-time applications due to its reduced hardware complexity.