Gaussian blurring with OpenCV: only blurring a subregion of an image?

Question

Is it possible to only blur a subregion of an image, instead of the whole image with OpenCV, to save some computational cost?

EDIT: One important po

Answer 1

If you are using javacv provided by bytecode

then you can do like this way. It will only blur particular ROI.

Mat src = imread("xyz.jpg",IMREAD_COLOR);
Rect rect = new Rect(50,50,src.size().width()/3,100);
GaussianBlur(new Mat(src, rect), new Mat(src, rect), new Size(23,23), 30);