title: Detect Low Light Condition and FaceRotation Angle in Degrees in Real-Time FaceDetection IOS
body: <p>I am writing an iOS app that will do <strong>real-time face-detection</strong> using iPhone's Front camera. </p>
  
  <p>In it, I need to check whether the lighting is proper or not. Like checking for "low light condition" or is left half light is more than right half light or vice versa. </p>
  
  <p>I am checking both OpenCV on iOS and the iOS default face-detction using <code>CIDetector</code> for one week but I am unable to find the solution. </p>
  
  <p>Any Ideas or samples will be helpful.</p>
  
  <p>In the same project iam using CIFaceFeature+FaceRotation to detect the face rotation angle its returning -1 to +1 values, but i need to show the values in 0 to 180 degrees (like user face is tilted 30 degrees)</p>
  
  <p>Thanks.</p>