Thanks for the quick reply! Yes, I have looked into both of those posts earlier and then especially the latter one which provided a few somewhat promising results, but not fully what I wanted - but I will revisit the examples again and see if I might have missed a possible solution there. If I’m allowed to dream, it would be awesome if the composition operation could be done using UMat instead of Mat too, since that’s what I’m using up until the point where I want to compose the images, to both be able to use the gpu and also to avoid conversion from UMat to Mat which I have realized is very expensive. But at this point I would be perfectly happy to have it working with Mat alone 