Question

I’d like to initialize a 3 by 3 cross-shaped kernel matrix and use it to dilate an image in OpenCV4Android. In native C++ OpenCV, you’d do:

Mat kernel = (Mat_<int>(3,3) << 0,1,0,1,1,1,0,1,0);
dilate(image, image, kernel);

but how can I do the equivalent of the first line in Java? A Mat cannot be treated like an array, and Java has no << operator. There seems to be an OpenCV function called cvCreateStructuringElementEx which initializes Mats for use as kernels, but I can’t find this function in OpenCV4Android.

Thanks so much.

Answer 1

I have never tried this but check if it works, at least this is the OpenCV4Android way to set a Structuring Element:

Mat kernel = Imgproc.getStructuringElement(Imgproc.MORPH_CROSS, new Size(3, 3));

Also, check out copyTo() method, it can receive a Mask:

src_mat.copyTo(dst_mat, mask);