title: how to assign a shape to an edge?
body: <p>I have an image with only black and white pixels. The image contains edges (the black pixels) with the width of one pixel (each black pixel has exactly one or two black neighbourpixels). Now i want to group the edges into different shape classes (e.g. line, triangle, ellipse). Problem: the edges are not perfect lines, triangles or ellipses. </p>
  
  <p>I think i can partially solve the problem by logical thinking. But i also have more complex geometries where this will be more difficult.</p>
  
  <p>Does anyone know how to solve this kind of problem? Or can anyone give me some ideas?</p>