Method for processing signals from a matrix for taking colour images, and corresponding sensor

Abstract

The invention relates to the processing operation of interpolating the colours of a Bayer mosaic image sensor. A first elementary matrix filter, which is a bilinear interpolation filter, of size m×m, m being an odd number larger than or equal to 3, a low-pass matrix filter of size n×n, n being an odd number larger than or equal to 3, and a high-pass matrix filter, complementary to the low-pass filter, of size n×n, are defined. The first matrix filter is convoluted with the low-pass filter, resulting in a low-frequency interpolation filter of size (m+n−1)×(m+n−1), and the first matrix filter is convoluted with the high-pass filter, resulting in a high-frequency interpolation filter of size (m+n−1)×(m+n−1). The matrix of digital signals arising from the pixels is filtered separately, using the pixels of each colour, by the low-frequency interpolation filter. The complete matrix of signals is filtered using the high-frequency interpolation filter. The result of the low-frequency filtering operation and the result of the high-frequency filtering operation are added together, for each pixel, in order to obtain a numerical value of a given colour of that pixel.