function [Cr Cg Cb]=comparagramrgb(r1,g1,b1,r2,g2,b2);
if nargin ~= 6
  error("comparagramrgb: must have 6 input arguments")
end%if
if nargout ~= 3
  error("comparagramrgb: must have 3 output arguments")
end%if

Cr=comparagram(r1,r2);
Cg=comparagram(g1,g2);
Cb=comparagram(b1,b2);