function m = pigment
%pigment	sets the pigmentation parameter (m) equal to one of the four 
%	default values, based on mean pigmentations of different groups. The 
%	groups are as follows:
%
%	Caucasian mean.							m = 0.142
%	mean blue-eyed Caucasian				m = 0.160
%	mean brown-eyed Caucasian				m = 0.106
%	mean pigmented-skin dark brown eye		m = 0.056
%
%	Values are from Ijspeert et al, 1992.
sentinel = 0;
while sentinel==0
	disp('Please specify the pigmentation parameter (m) that you would like to use:')
	disp('	1 = Caucasian mean (0.142)')
	disp('	2 = mean blue Caucasian (0.160)')
	disp('	3 = mean brown Caucasian (0.106)')
	disp('	4 = mean pigmented-skin dark-brown eye (0.056)')
	n=input(' ','s');
	n = str2num(n);
	switch n;
		case{1}
		m = 0.142;
		sentinel = 1;
		case{2}
		m = 0.160;
		sentinel = 1;
		case{3}
		m = 0.106;
		sentinel = 1;
		case{4}
		m = 0.056;
		sentinel = 1;
		otherwise
		disp('That is an incorrect value. Please Try again');
	end
 end