How to find mean square error of row mean values?

close all;
clear all;
clc;
Dir = 'F:\Stuff\Dataset\SignDataset_Sobel\';
count=0;

for i = 1:208
    xImgs = imread([Dir,int2str(i),'.jpg']); 
    [r c pl] = size(xImgs);
    xImgs = double(xImgs);

      %%---- DCT-----%%
      red = dct(xImgs(:,:,1));
      green = dct(xImgs(:,:,2)); 
      blue = dct(xImgs(:,:,3));

      xr = zeros(1,128);
      xg = zeros(1,128);
      xb = zeros(1,128);

      %%--- Row Mean----%%
      for xi=1:128
          xr(i,xi) = mean(red(xi,:));
          xg(i,xi) = mean(green(xi,:));
          xb(i,xi) = mean(blue(xi,:));
      end

%      xImgs_temp(:,:,1) = xr;
%      xImgs_temp(:,:,2) = xg;
%      xImgs_temp(:,:,3) = xb;

       xImgs_temp = cat(3,xr, xg, xb);
      for j=1:208
          count=count+1;  

          xmse_temp(count,1)=0;
          xmse_temp(count,2)=i;
          xmse_temp(count,3)=j;

          totalcat=0;
          xmse_temp = double(xmse_temp);
          xImg=imread([Dir,int2str(j),'.jpg']);
          [r,c,pl] = size(xImg);
          xImg = imresize(xImg,[r c]);
          xImg = double(xImg);

          %--- DCT---%
          red1 = dct(xImg(:,:,1));
          green1 = dct(xImg(:,:,2)); 
          blue1 = dct(xImg(:,:,3));

          xr1 = zeros(1,128);
          xg1 = zeros(1,128);
          xb1 = zeros(1,128);

          %%---- Row Mean---%%
          for xj=1:128
              xr1(j,xj) = mean2(red1(xj,1:c));
              xg1(j,xj) = mean2(green1(xj,1:c));
              xb1(j,xj) = mean2(blue1(xj,1:c));
          end

%         xImg_temp(:,:,1) = xr1;
%         xImg_temp(:,:,2) = xg1;
%         xImg_temp(:,:,3) = xb1;

          xImg_temp = cat(3,xr1,xg1,xb1);
          for xi=1:r
            for xj=1:c
                for xk=1:3
                  xmse_temp(count,1) = xmse_temp(count,1)+((xImgs_temp(xi,xj,xk)-xImg_temp(xi,xj,xk)) *(xImgs_temp(xi,xj,xk)-xImg_temp(xi,xj,xk)));
                end
            end
          end
           xmse_temp(count,1)=xmse_temp(count,1)/(3*r*c);
           fprintf('MSE of %f with %f is :%f\n',xmse_temp(count,2),xmse_temp(count,3),xmse_temp(count,1));
      end

end

when i applied only DCT it shows the MSE but when on DCT i applied this row mean then i want to find MSE but it shows this, It shows the following error:

Attempted to access xImgs_temp(2,1,1); index out of bounds because size(xImgs_temp)=[1,128,3].

Error in mse_trial (line 72)
                xmse_temp(count,1) = xmse_temp(count,1)+( (xImgs_temp(xi,xj,xk)-xImg_temp(xi,xj,xk)) *(xImgs_temp(xi,xj,xk)-xImg_temp(xi,xj,xk)));

Answer 1

[Image Analyst]

In the Image Processing Toolbox, there is an immse() function. Assuming you have a reference, "ground truth" image, use immse().