gusucode.com > Diabetic retinopathy > colourfulness_metric.m
function score = colourfulness_metric(img) if (nargin > 1) % Number of input argument score = -1; return; end [M N d] = size(img); if(d~=3) sprintf('Not a color image') score=-1; return end x = double(img); R=x(:,:,1); G=x(:,:,2); B=x(:,:,3); alpha= R-G; beta=(R+G)/2-B; sigma_a=std2(alpha); sigma_b=std2(beta); mu_a=mean2(alpha); mu_b=mean2(beta); score=sqrt(sigma_a*sigma_a+sigma_b*sigma_b)+0.3*sqrt(mu_a*mu_a+mu_b*mu_b); return