A method of improving a color filter array image from an image sensor having a plurality of color channels and a panchromatic channel, wherein: the image sensor has a color filter array on pixels of the image sensor, wherein the color filter array contains red, green, blue and panchromatic pixels; the color filter array image is an image captured using the image sensor having the color filter array on its pixels; each color channel refers to image values corresponding to a color filter of a respective one of red, green, blue; the panchromatic channel refers to image values corresponding to the panchromatic filter; the method comprising: (a) capturing the panchromatic channel at a shorter exposure time than at least one of the plurality of color channels with the image sensor; (b) binning the color pixels such that the color pixels collectively form a low resolution Bayer pattern wherein each low-resolution Bayer pattern pixel comprises one respective color pixel value corresponding to a Bayer pattern; (c) performing color filter array interpolation upon the low resolution Bayer pattern to generate interpolated color values for each low-resolution Bayer pattern pixel; (d) at each low-resolution Bayer pattern pixel computing a respective luminance value from the interpolated color values thereof thereby generating a luminance channel which is comparable to the panchromatic channel; and (e) summing pairs of panchromatic pixel values of the captured panchromatic channel to generate a panchromatic channel at the same spatial resolution as the luminance channel; (f) initially classifying all pixels of the low-resolution Bayer pattern as defective; computing a color difference at each pixel of the low-resolution Bayer pattern, the color difference being defined as C-L, where C is the colour value of a low-resolution Bayer pattern pixel, and L is the corresponding luminance value of said luminance channel; for each low-resolution Bayer pattern pixel, averaging the color differences of pixels that have a matching spatial location in the Bayer pattern in a window of radius k pixels centered on the pixel to provide an average color difference value for the pixel, and adding the average color difference value for the pixel to the panchromatic value for the pixel to produce an improved color value for the pixel. the image sensor has a color filter array on pixels of the image sensor, wherein the color filter array contains red, green, blue and panchromatic pixels; the color filter array image is an image captured using the image sensor having the color filter array on its pixels; each color channel refers to image values corresponding to a color filter of a respective one of red, green, blue; the panchromatic channel refers to image values corresponding to the panchromatic filter; the method comprising: (a) capturing the panchromatic channel at a shorter exposure time than at least one of the plurality of color channels with the image sensor; (b) binning the color pixels such that the color pixels collectively form a low resolution Bayer pattern wherein each low-resolution Bayer pattern pixel comprises one respective color pixel value corresponding to a Bayer pattern; (c) performing color filter array interpolation upon the low resolution Bayer pattern to generate interpolated color values for each low-resolution Bayer pattern pixel; (d) at each low-resolution Bayer pattern pixel computing a respective luminance value from the interpolated color values thereof thereby generating a luminance channel which is comparable to the panchromatic channel; and (e) summing pairs of panchromatic pixel values of the captured panchromatic channel to generate a panchromatic channel at the same spatial resolution as the luminance channel; (f) initially classifying all pixels of the low-resolution Bayer pattern as defective; (a) capturing the panchromatic channel at a shorter exposure time than at least one of the plurality of color channels with the image sensor; (b) binning the color pixels such that the color pixels collectively form a low resolution Bayer pattern wherein each low-resolution Bayer pattern pixel comprises one respective color pixel value corresponding to a Bayer pattern; (c) performing color filter array interpolation upon the low resolution Bayer pattern to generate interpolated color values for each low-resolution Bayer pattern pixel; (d) at each low-resolution Bayer pattern pixel computing a respective luminance value from the interpolated color values thereof thereby generating a luminance channel which is comparable to the panchromatic channel; and (e) summing pairs of panchromatic pixel values of the captured panchromatic channel to generate a panchromatic channel at the same spatial resolution as the luminance channel; (f) initially classifying all pixels of the low-resolution Bayer pattern as defective; computing a color difference at each pixel of the low-resolution Bayer pattern, the color difference being defined as C-L, where C is the colour value of a low-resolution Bayer pattern pixel, and L is the corresponding luminance value of said luminance channel; for each low-resolution Bayer pattern pixel, averaging the color differences of pixels that have a matching spatial location in the Bayer pattern in a window of radius k pixels centered on the pixel to provide an average color difference value for the pixel, and adding the average color difference value for the pixel to the panchromatic value for the pixel to produce an improved color value for the pixel.