A method of processing image signals using an image sensor having an array of image sensor pixels and processing circuitry , wherein the array of image sensor pixels includes a first group of image sensor pixels responsive to light of a first color, a second group of image sensor pixels responsive to light of a second color, and a third group of image sensor pixels responsive to light of a third color corresponding to a range of light frequencies broader than that of the first color and of the second color, the method comprising: with the first group of image sensor pixels , generating first image signals in response to light of the first color; with the second group of image sensor pixels , generating second image signals in response to light of the second color; with the third group of image sensor pixels , generating third image signals in response to light of the third color; and with the processing circuitry demosaicing the first image signals for obtaining first image data, demosaicing the second image signals for obtaining second image data and demosaicing the third image signals for obtaining third image data, subtracting from the first image data the third image data for generating first differential image data and subtracting from the second image data the third image data for generating second differential image data, performing chroma filtering operations on the first differential image data and on the second differential image data, adding said third image data on the filtered first differential image data for generating first filtered data and adding the third image data on the filtered second differential image data for generating second filtered data to increase the noise correlations amongst the first, second and third data, and applying a color correction matrix to the first filtered data, the second filtered data and the third image data, wherein the color correction matrix is configured to extract fourth image data representing a fourth color from the third image data. with the first group of image sensor pixels , generating first image signals in response to light of the first color; with the second group of image sensor pixels , generating second image signals in response to light of the second color; with the third group of image sensor pixels , generating third image signals in response to light of the third color; and with the processing circuitry demosaicing the first image signals for obtaining first image data, demosaicing the second image signals for obtaining second image data and demosaicing the third image signals for obtaining third image data, subtracting from the first image data the third image data for generating first differential image data and subtracting from the second image data the third image data for generating second differential image data, performing chroma filtering operations on the first differential image data and on the second differential image data, adding said third image data on the filtered first differential image data for generating first filtered data and adding the third image data on the filtered second differential image data for generating second filtered data to increase the noise correlations amongst the first, second and third data, and applying a color correction matrix to the first filtered data, the second filtered data and the third image data, wherein the color correction matrix is configured to extract fourth image data representing a fourth color from the third image data. <EOS>