title: Morphology skeleton - differences betwen scikit-image, pymorph, OpenCV-Python?
body: <p>I noticed significant differences in skeleton geometry between various python scientific graphics oriented packages.</p>
  
  <p>Skeleton using OpenCV-Python:</p>
  
  <p><img src="https://i.stack.imgur.com/CWi8H.png" alt="Skeleton using OpenCV-Python"></p>
  
  <p>Skeleton using pymorph:</p>
  
  <p><img src="https://i.stack.imgur.com/f4Wrq.png" alt="Skeleton using pymorph"></p>
  
  <p>Skeleton using scikit-image:</p>
  
  <p><img src="https://i.stack.imgur.com/RMrtU.png" alt="Skeleton using scikit-image"></p>
  
  <p>As one can observe OpenCV-Python and pymorph produce the same skeleton but scikit-image does not. What is the reason for skeletons' differences? Which one is proper skeleton?</p>