title: Error: nonconformant arguments (op1 is 1x3, op2 is 1x2)
body: <p>I am trying to do stone detection in Octave and this is error happening: </p>
  
  <blockquote>
    <p>error: imarithmetics: mx_el_eq: nonconformant arguments (op1 is 1x3, op2 is 1x2)<br>
    error: called from; imarithmetics at line 35 column 13; imadd at line 43 column 12; stones at line 24 column 7</p>
  </blockquote>
  
  <p>I want to superposition the erode image with the original one. I can't figure it out what to do with this.</p>
  
  <pre><code>pkg load image
  
  img = imread ('stones.jpg');
  bw = rgb2gray(img);
  
  k = ones(3,3)/9;
  m = imfilter(bw,k);
  K = wiener2 (m, [5 5]);
  subplot(1,3,1),imshow(bw);
  subplot(1,3,2),imshow(m);
  subplot(1,3,3),imshow(K);
  
  thresh = im2bw(K);
  figure, imshow(thresh);
  
  
  se = strel("square", 3);
  se =[1, 1, 1;1, 1, 1;1, 1, 1];
  OP = imerode(thresh, se);
  OP = imerode(OP, se);
  OP = imerode(OP, se);
  figure, imshow(OP);
  
  final = imadd(img,OP,'uint16'); %&lt;&lt; Line 24, error happens here
  figure, imshow(final);
  </code></pre>