The following two procedures, histogram equalisation and SLCE, work by altering the LUT and not the image itself. SLCE - Saturated Linear Contrast Enhancement SLCE uses the Histogram subroutine data to increase the image contrast. It works by the following method. The ideal image histogram would be flat, maximising the image contrast. This subroutine attempts to do just that.
H in is the standard image histogram.
Evenly distributes image gray values across screen gamut. This is why the resulting histogram is so sparse. However, we decided that the advantages outweighed the disadvantages. These 9 values are then summed, and the central image pixel is given this value. This transformation is carried out on every pixel in the image.