Fuzzy logic device for image noise reduction

Abstract

A fuzzy device for image noise reduction, includes an interface adapted to retrieve the gray level of a pixel to be processed of an image and of neighbouring pixels; a difference circuit connected to the interface and adapted to generate a difference of the gray levels between said neighbouring pixels and said pixels to be processed; a fuzzy flat area smoothing circuit connected to the difference circuit and adapted to perform a low-pass smoothing of an almost homogeneous region defined by said pixel and by said neighbouring pixels; an edge preserving smoothing circuit connected to the difference circuit and adapted to perform low-pass filtering on a high-frequency information region defined by the pixel and by the neighbouring pixels; a region voter circuit connected to the interface and adapted to give a measure for considering whether the region defined by the pixel and the neighbouring pixels is almost homogeneous; and a soft switching circuit connected to the outputs of the smoothing circuit and adapted to perform the weighting of the outputs of the smoothing circuit on the basis of the measure.