title: directional edge detection in OpenCV
body: <p>I would like to detect edge that has certain angle/orientation.</p>
  
  <p>Adapting from a post in SO, I've figured out to use OpenCV magnitude, phase and Sobel functions to filter out unwanted edge points. Then use the magnitude image (with phase image as condition) to output the edge points.</p>
  
  <p>However, the results is not similar to Canny edge function. It's good that the edges with unwanted angles are filtered out but detected edges are blobs of points, not thin line edge</p>
  
  <p><img src="https://i.stack.imgur.com/Qb7so.jpg" alt="enter image description here"></p>
  
  <p>the left edge image is also plotted out after findContours is used, but this barely helps out</p>
  
  <p>1) what else should be added to mimic Canny processing?</p>
  
  <p>2) As for the purpose of directional edge detection, is this approach more robust than using a directional kernel other than typical Sobel ones?</p>
  
  <p>Thank you!</p>
  
  <p>Edit 01:</p>
  
  <p>forgot to put my code <a href="http://pastebin.com/Vzi6PCkt" rel="nofollow noreferrer">link</a></p>