title: Find slope (angle) of each line of the image
body: <p>I have to calculate a slope (or an angle) of every single detectable line of the image. And even to detect the changes of the slope of the line, if it is possible.
  I've performed 2D Fourier and I know a neighborhood averege angle at every area (sets of 64x64px). I even try a Hough transform, but neither sobel nor prewitt edge detection seems to detect these lines appropriately.<br><br>
  Please note that some of the lines are crossing each other, and some aren't straight.<br><br>
  Is there a method to detect the slope of each line? Or to detect these lines in order to perform an usefull Hough transform?</p>
  
  <p>If you need the full image I can upload it somewhere. </p>
  
  <p><a href="http://i56.tinypic.com/2uohto8.jpg" rel="nofollow">Image</a></p>