title: convert Bitmap to Mat after capture image using android camera
body: <pre><code>Mat b = new Mat();
  Bitmap bmp = getIntent().getExtras().getParcelable("image_send");
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_display_image);
      Mat tmp = new Mat (bmp.getWidth(), bmp.getHeight(), CvType.CV_8UC1);
      Utils.bitmapToMat(bmp, tmp);
      Imgproc.cvtColor(tmp, tmp, Imgproc.COLOR_RGB2GRAY);
      //Imgproc.cvtColor(tmp, tmp, Imgproc.COLOR_GRAY2RGB, 4);
      Utils.matToBitmap(tmp, bmp);
  
      iv = (ImageView) findViewById(R.id.imageView1);
      iv.setImageBitmap(bmp);
  }
  </code></pre>
  
  <p>Can't display the bmp. My app has stopped after taking a picture.</p>