private void initCamera() {
    SurfaceView cameraSurface = (SurfaceView) findViewById(R.id.surface_camera);
    cameraView_ = new CameraView(cameraSurface);
    cameraView_.setCameraReadyCallback(this);

    overlayView_ = (OverlayView) findViewById(R.id.surface_overlay);
    overlayView_.setOnTouchListener(this);
    overlayView_.setUpdateDoneCallback(this);
  }