Plotting maximum intensity value

I wrote the following code to plot the maximum intensity value in an Infrared image.It had shaded of white and black so I have thresholded it.But I don't find the output to be accurate.Can anyone help me out in correcting the code.

function [row col] = maximum( X )

[r c] = size(X);

for i=1:r
  for j=1:c
      if X(i,j)>140 && X(i,j)<160
          temp(i,j) = X(i,j);
      else
         temp(i,j) = 1;
      end
      if temp(i,j) == max(max(temp))
          row = i;
          col = j;
      end 
  end
end

end
x0 = rgb2gray(imread('img_1.jpg'));
x1 = rgb2gray(imread('img_2.jpg'));
[row0 col0] = maximum(x0);
[row1 col1] = maximum(x1);  
figure(1)
plot(row0,col0,'+',row1,col1,'d')

Any help will be appreciated.

Answer 1

[Sean de Wolski]

[the_mx, idx] = max(X(:))
[row_mx, col_mx] = ind2sub(size(X),idx);

[Harsha Vardhan Rao Avunoori]

Thanks Sean it worked!!! I can plot the max value now :)