Android FaceDetector.findFaces找不到任何面孔

Question

This is a code I have written to run android's face detector. Unfortunately, it doesn't find any. I have put this in a onPreviewFrame(data, camera).

Camera.Parameters parameters = camera.getParameters();
Camera.Size size = parameters.getPreviewSize();
YuvImage image = new YuvImage(data, ImageFormat.NV21, size.width, size.height, null);
Rect rectangle = new Rect(0, 0, size.width, size.height);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
int quality = 100;
image.compressToJpeg(rectangle, quality, stream);
Bitmap bitmap = BitmapFactory.decodeByteArray(stream.toByteArray(), 0, stream.size());
FaceDetector detector = new FaceDetector(size.width, size.height, 5);
FaceDetector.Face[] faces = new FaceDetector.Face[5];
int numFaces = detector.findFaces(bitmap, faces);
textView.setText("numFaces = " + numFaces);

Any ideas? fixes?

Answer 1

I think you should check whether your bitmap data is correct firstly. You must setPreviewSize before startPreview . check whether the size is same as your preview data. or you can hard code it to (640, 480) for a test. If your bitmap is correct. maybe the API cannot work due to the input data quality. you can dump some data, and try other app or lib, such as OpenCV, to verify. Good luck.