Android camera2 face detection

Question

There is not enough info about camera2 face detection mechanism. I used Camera2 sample from Google: https://github.com/android/camera-samples

I set face detection mo

Answer 1

I found that only in case STATE_PREVIEW, you can process the result to show faces lenth. Change from

private CameraCaptureSession.CaptureCallback mCaptureCallback
        = new CameraCaptureSession.CaptureCallback() {

    private void process(CaptureResult result) {
        Integer mode = result.get(CaptureResult.STATISTICS_FACE_DETECT_MODE);
        Face[] faces = result.get(CaptureResult.STATISTICS_FACES);
        if(faces != null && mode != null) {
            Log.e("tag", "faces : " + faces.length + " , mode : " + mode);
        }

        switch (mState) {
            case STATE_PREVIEW: {
                // We have nothing to do when the camera preview is working normally.
                break;
            }
...

to

private CameraCaptureSession.CaptureCallback mCaptureCallback
        = new CameraCaptureSession.CaptureCallback() {

    private void process(CaptureResult result) {


        switch (mState) {
            case STATE_PREVIEW: {
              Face[] faces = result.get(CaptureResult.STATISTICS_FACES);
              if (faces != null && faces.length > 0) {
                  Log.e("tag", "faces : " + faces.length);
              }
                break;
            }

Please try this to see if it works.