1. Field of the Invention
The invention relates to the filtering of picture representation signals, the term "picture signal" being taken in a very general sense and as designating any signal representing data having a two dimensional distribution, which will be considered hereafter for the sake of simplicity as designating a feature (for example luminance, contrast or chrominance) of a picture pixel.
The invention has an important an application in the field of installations for real time picture processing, which often require convolution filtering operations.
2. Prior Art
Numerous picture filtering devices already exist in the form of large scale integrated circuits. One of the major problems met with in the construction of such devices is the high number of pins required for feeding the filtering coefficients into the circuit, when the size of the convolution kernel is high. In fact, the usual devices carry out in parallel, on each pixel in turn, all the partial products required for the matrix multiplication by lines and/or columns of the matrix of the convolution kernel.
Attempts have been made to solve that problem, for instance by modifying the sequence of mathematical manipulations, as described for instance in Chambers U.S. Pat. No. 4,720,871 but with limited results.