Signed Pixels : advantages
n  Signed pixels seem at first to be counter-intuitive but they have numerous advantages. nA value of 0 or mid grey can be viewed as the ‘most likely’ value that a pixel takes on in the absence of other information. nIf you do arithmetic on images, in particular subtract one image from another, then negative values of pixels naturally arise. nSigned pixels allow straightforward implementation of contrast adjustments. For instance multiplying an image by 0.5 halves the contrast in the image.
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