title: Error when using cv::addWeighted
body: <p>I was walking through an example, and got an error on the following line after running the code</p>
  
  <pre><code>cv::addWeighted(temp_image, 1.0, noise_image, 1.0, 0.0, temp_image);
  </code></pre>
  
  <p>This is the error:</p>
  
  <blockquote>
    <p>libc++abi.dylib: terminating with uncaught exception of type
    cv::Exception:
    /Users/abd/Documents/opencv-3.0.0/modules/core/src/arithm.cpp:1987:
    error: (-209) The operation is neither 'array op array' (where arrays
    have the same size and the same number of channels), nor 'array op
    scalar', nor 'scalar op array' in function arithm_op</p>
  </blockquote>
  
  <p>This is the error. How can I solve it?</p>
  
  <p>Thanks.</p>