1. A method of improving a first color filter array image from an image sensor having a plurality of color channels and a panchromatic channel, comprising: (a) capturing the panchromatic channel at a different exposure time than at least one of the plurality of color channels with the image sensor; (b) using the plurality of color channels to provide a luminance channel; and (c) analyzing the first color filter array image and the luminance channel to determine defective pixels in the plurality of color channels, wherein a defective pixel is a pixel whose luminance value does not match a corresponding panchromatic value, and using neighboring color and luminance pixel values to improve the defective pixels to produce a second color filter array image or full-color image having at least one improved channel, including for each of the defective pixels, computing a color difference between a color value of at least one of the color channels and a luminance value of the luminance channel, and adding the color difference to a panchromatic value of the panchromatic channel to improve each defective pixel.