title: What does cv2.cornerHarris return?
body: <p>I have been reading about <code>cornerHarris</code> in OpenCV. I read through the <a href="https://docs.opencv.org/2.4/doc/tutorials/features2d/trackingmotion/harris_detector/harris_detector.html" rel="nofollow noreferrer">documentation</a> but I am not sure what does this function return.</p>
  
  <p>While reading through the <a href="https://docs.opencv.org/3.0-beta/doc/py_tutorials/py_feature2d/py_features_harris/py_features_harris.html" rel="nofollow noreferrer">examples</a>, there is a statement written as:</p>
  
  <pre><code>dst = cv2.cornerHarris(gray,2,3,0.04)
  
  img[dst&gt;0.01*dst.max()]=[0,0,255]
  </code></pre>
  
  <p>I just cannot understand the second statement above, may be because I do not understand, what is <code>cornerHarris</code> actually returning.</p>
  
  <p>I do sense, that there is some kind of threshold being applied, but I cannot explain.</p>