A method for reconstructing a colour image acquired by a photosensitive sensor covered with a mosaic of filters of different colours making up a base pattern, obtaining the product of a demosaicing matrix with a matrix representation of a mosaic image coming from the sensor following acquisition of the colour image by the sensor, the product of the demosaicing matrix with the matrix representation of the mosaic image performing an interpolation of the colour of each pixel of the mosaic image as a function of a pixel neighbourhood of a base pattern corresponding to the base pattern of the mosaic of filters.