psnr.m

Block Recovery code - matlab

function [PSNR,mse]=psnr(X,Y)

if nargin<2, D=X;
else
   if any(size(X)~=size(Y)), error('The input size is not equal to each other!'); end
   D=X-Y;
end
err=X-Y;
mse=sum(D(:).*D(:))/prod(size(X));
PSNR = 20*log10(256/std(err(:)))-4;