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javaandroidface-detection

Why are eye coordinates not detected with FaceDetectionListener for Android

I am working on an Android app that does face and eye detection using the FaceDetection API for Android. I am able to detect and draw rectangles around faces but however I cannot figure out why all my eye coordinates are getting set to (0,0).

Reading this documentation, I see that the eye detection is not supported on all devices but it says that the Point objects are set to null, not (0,0) so I don't understand what is going on here.

Here is my FaceDetectionListener:

private List<Rect> faceRects;
private Point leftEye;
private Point rightEye;

@Override
public void onFaceDetection(Camera.Face[] faces, Camera camera) {
    if (faces.length > 0) {
        faceRects = new ArrayList<Rect>();

        for (int i = 0; i < faces.length; i++) {
            int left = faces[i].rect.left;
            int right = faces[i].rect.right;
            int top = faces[i].rect.top;
            int bottom = faces[i].rect.bottom;
            Rect uRect = new Rect(left, top, right, bottom);
            faceRects.add(uRect);

            leftEye = faces[i].leftEye; //***THIS IS (0,0) EVEN WHEN FACE IS DETECTED
            rightEye = faces[i].rightEye;
        }
    }
}

Why are my Points for eye coordinates getting set to (0,0). I am testing on a Galaxy S7 and I find it hard to believe that it doesn't support eye detection. I am open to a solution to this problem using OpenCV as well but I'd rather stick with the Android SDK since I can already detect the faces (if possible). Thank you for the assistance.

Solution

  • Not all devices support all the face features.

    As the documentation states for leftEye and most of the other fields:

    This is an optional field, may not be supported on all devices. If not supported, the value will always be set to null. The optional fields are supported as a set. Either they are all valid, or none of them are.

    Only the Face.rect and Face.score fields are guaranteed to be included if face detection is supported by the device.