public synchronized void stopPreview() {
    if (autoFocusManager != null) {
    	autoFocusManager.stop();
    	autoFocusManager = null;
    }
  	if (camera != null && previewing) {
      camera.stopPreview();
      previewCallback.setHandler(null, 0);
      previewing = false;
    }
  }
Tells the camera to stop drawing preview frames.
OCRTest/src/main/java/edu/sfsu/cs/orange/ocr/camera/CameraManager.java