opencv - convert Bitmap to Mat after capture image using android camera

Question

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);
}

Can't display the bmp. My app has stopped after taking a picture.

Answer 1

Utils.bitmapToMat converts an Android Bitmap to an OpenCV Mat. It requires a bitmap of type ARGB_8888 or RGB_565.

import org.opencv.android.Utils;

Mat mat = new Mat();    
Bitmap bmp32 = bmp.copy(Bitmap.Config.ARGB_8888, true);
Utils.bitmapToMat(bmp32, mat);