When combining three grayscale images into a color composite, the three images are often (unsurprisingly) quite similar. Simply mapping one to a red grayscale, one to green, and one to blue results in a color image which looks very "washed out".

One approach to accentuating the differences is to enhance colors by adjusting the red/green/blue values for a pixel as follows: find the maximum of the three input values and scale the others downward by taking a power of their fraction of this maximum.

So, for instance, if the three values are

    red:   140
    green: 105
    blue:  201

and the "enhancement factor" is 2.0, then

    red   -> (140/201)^2.0 * 201 =  97
    green -> (105/201)^2.0 * 201 =  55
    blue  -> (201/201)^2.0 * 201 = 201

and the pixel goes from somewhat blue to very blue. The visual affect is to "enhance" the color without changing very much the perceived intensity.

In practice using enhancement factors over about 3.0 results in colors which are too garish (though of course this depends on how close the unenhanced image would be to "gray". We have allowed in the interface for values ranging from 1.0 (no enhancement) to 3.0 in 0.5 increments.