title: OpenCv Python (CTypes) detection of tilted face
body: <p>I have a not-so-simple question.</p>
  
  <hr>
  
  <p><strong>The Situation:</strong></p>
  
  <p>I'm working on robust facial detection API in python written on top of OpenCV (cv not cv2).</p>
  
  <p>I am using Haar Cascades for face detection specially</p>
  
  <p>front - haarcascade_frontalface_default.xml</p>
  
  <p>profile - haarcascade_profileface.xml</p>
  
  <p>Each worker is using different harr classifier (front/profile) and produce the set of ROI (Region of Interests) then do a uion on them and merge all overlaping bouding boxes.</p>
  
  <p>The result is "your casual red square" around a face with 70% accuracy and not so may phantom faces.</p>
  
  <hr>
  
  <p><strong>The problem:</strong></p>
  
  <p>Simply tilting the face. My algorithm cannot detect a tilted face.</p>
  
  <p>For profile detection I did a simple flip of a image to detect both left and right profile.</p>
  
  <p>I was thinking there "should" be a better way to detect a tilted face than to call algorithm multiple times for multiple slightly rotated images. (This is a only solution that came to my mind).</p>
  
  <hr>
  
  <p><strong>The question:</strong></p>
  
  <p>Is there a approach or a way or a specific harr classifier for detection of tilted faces?</p>
  
  <p>Thank you :)</p>