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Contrast Enhancement Against a Constant Background

Dale-Jones R & Tjahjadi T

Proc. 7th Scandinavian Conf. on Image Analysis, vol II, 1991, 894-901


This paper presents a technique for enhancing the contrast in an image. The algorithm spaces out the grey level bins in the image histogram according to the results of a visual experiment. This experiment determines the ability of the eye to distinguish grey levels from each other against a constant background, the Just Noticeable Difference (JND). The experiment gave different results depending on the monitor on which it was conducted, because of their different display capabilities. The algorithm uses a look up table (lut) of JNDs determined by the experiment, so that if the lut is changed for the particular monitor, the result of processing an image with the algorithm will appear the same on each monitor.

The result of using the algorithm on a holographic image is compared with the results of two comparable algorithms: contrast stretching and histogram hyperbolization.