compc_cpc

function PSNR = compc_cpc(imagem, tx)
  Im = imread(imagem);

  #imwrite(Im,"img.jp2","CompressionRatio",tx);
  imwrite(Im,"img.jp2");

  Im_c = imread("img.jp2");
  imshow(Im_c);

  memsize = numel(Im);
  disk_size = imfinfo("img.jp2").FileSize;
  taxa_comp = memsize / disk_size;

  if length(size(Im)) == 3
    Im = rgb2ycbcr(Im);
    Im_c = rgb2ycbcr(Im_c);
    Im = Im(:,:,1);
    Im_c = Im_c(:,:,1);
  endif

  MSE = sum(sum((Im .- Im_c).^2)) / (rows(Im) * columns(Im));
  if MSE == 0
    PSNR = inf
  else
    PSNR = 10 * log10((2^8 - 1)^2/MSE);
  endif
endfunction