Processing device for video signals

Abstract

A processing device for video signals has a memory device suitable to store discrete image elements of a video field and a filtering device supplied by the memory device and suitable to recover errors introduced by the memory device. The filtering device includes a filter, noise detector means, and soft-switch means. The filter has an input supplied with digital signals representative of values of a plurality of discrete image elements and comprises an image element to be examined and neighboring image elements. The discrete image elements is stored in the memory device, and an output supplying digital signals representative of a filtered value of the image element to be examined. The noise detector means operating on fuzzy-logic rules has an input supplied with the digital signals representative of the plurality of values of the image elements and an output supplying a weight signal representative of a degree of erroneousness of the discrete image element to be examined. The noise detector circuit determines the degree of erroneousness by comparing the value of the image element to be examined with the values of the neighboring image elements. The soft-switch means has a first, second and third input and an output. The first input is supplied with the digital signals representative of the value of the image element to be examined. The second input is supplied with the output of the filter. The third input is supplied with the weight signal. The output supplies digital signals representative of a weighted average of the output of the filter and of the digital signals representative of the value of the image element to be examined according to respective weights determined by the degree of erroneousness.