Support Histogram Contrast Stretching in GeoTools Rasters

I'd like to support histogram-statistical contrast stretching on rasters, specifically in ArcSDE, but possibly as a general filter for GridCoverages

See http://www.fas.org/irp/imint/docs/rst/Sect1/Sect1_12a.html

The idea is that you create a histogram of the colors a particular image, then calculate the mean pixel color and the standard deviation around that mean. You then consider the minimum pixel value of mean-(n*stddev) and the maximum pixel value of mean+(n*stddev). You then set the min pix val to image-output color zero, and the max pix val to image-output-color 255. Then you interpolate the remaining colors in the image into the 'stretched' color-space, causing higher contrast for the densest portion of the color-space.