title: Contour approximation containing undesired points
body: <p>Hi there i have a polygon problem. I don't know what to look for so i decided to ask here. The image below shows a simple shape. The contours are detected with OpenCV's <a href="http://docs.opencv.org/doc/tutorials/imgproc/shapedescriptors/find_contours/find_contours.html" rel="noreferrer">findContours()</a> and aproximated by the <a href="http://www-prima.inrialpes.fr/perso/Tran/IEEE-PAMI/1989/Teh89-PAMI.pdf" rel="noreferrer">CV_CHAIN_APPROX_TC89_KCOS</a> (for those who want to know how this is done) algorithm, so that all points in a line, are summarized to a single line.
  So anyways some contours contain some sort of, i call it noise, in the shape. The image below shows what is meant with noise. The red line is the contour. (Sorry no ms paint skills)</p>
  
  <p><img src="https://i.stack.imgur.com/M6OMA.png" alt="enter image description here"></p>
  
  <p>My goal is to redefine the shape to approximate the shape, but leave out this "noise". So the contour should look like this. The blue line shows the corrected contour.</p>
  
  <p><img src="https://i.stack.imgur.com/PiDwu.png" alt="enter image description here"></p>