c++, opencv: Is it safe to use the same Mat for both source and destination images in filtering operation?

Question

Filtering operations involve convolutions and the filtered value at position (x,y) will also depend on the intensities of pixels (x-a,y-b) with a,b >0.

So using directly as destination the same image will lead to unexpected behaviors because during calculation I'm taking some already-filtered data instead of original ones.

Question

Does opencv manage this issue internally in functions like cv::GaussianBlur(.) , cv::blur, etc? Is it safe to give a reference to the same Mat to both src and dst parameters? thanks

Answer 1

Yes, there would not be any problem if you do so. I have done such thing several time. openCV will automatically take care of it.

I tested the following code and it works perfect:

int main(int argc, char* argv[])
{
    Mat src;
    src = imread("myImage.jpeg", 1);
    imshow("src", src); //Original src

    cv::blur( src, src, Size(25,25) , Point(-1,-1), BORDER_DEFAULT );

    imshow("dst", src); //src after blurring

    waitKey(0);
}