title: iOS OpenCV haarcascade for other facial emotions
body: <p>I have been trying OpenCV iOS sample to achieve facial emotion recognition.
  I got OpenCV sample iOS project 'openCViOSFaceTrackingTutorial' from below link.
  <a href="https://github.com/egeorgiou/openCViOSFaceTrackingTutorial/tree/master/openCViOSFaceTrackingTutorial" rel="noreferrer">https://github.com/egeorgiou/openCViOSFaceTrackingTutorial/tree/master/openCViOSFaceTrackingTutorial</a></p>
  
  <p>This sample project uses 'face detection', it works fine. It uses 'haarcascade_frontalface_alt2.xml' trained model.</p>
  
  <p>I want to use the same project but have haarcascade for other facial emotions like Sad, Surprise. I have been searching for how to train haarcascade for emotions like Sad, Surprise etc. but couldn't find any clue.</p>
  
  <p>Could someone advise me, how to train haarcascade for emotions like Sad, Surprise etc. to use in this sample OpenCV iOS project? Or will there be readymade haarcascade for emotions like Sad, Surprise etc. to use for this iOS sample.</p>
  
  <p>Thanks</p>