Introduction - If you have any usage issues, please Google them yourself
Normalises image values to 0-1, or to desired mean and variance
Usage:
n = normalise(im)
Offsets and rescales image so that the minimum value is 0
and the maximum value is 1. Result is returned in n. If the image is
colour the image is converted to HSV and the value/intensity component
is normalised to 0-1 before being converted back to RGB.