[dr_zoidberg]

When I moved some projects from OpenCV 3 to 4 I got a nice speed up pretty much everywhere, some things no speed up at all and some others pretty big. I can't really remember the numbers, but at the moment it was a global 10 to 20% perf improvement just on updating a library.

Might want to check that. Also 4.something got SIFT as part of OpenCV (instead of living in the contrib module) because the patent expired and you can now use it for free.

As for blowing up with NN packages and such... I don't really use those parts, but if the NN module had easier support to run networks trained on popular frameworks I might've used it. Disclaimer: it's been quite a while since I last tried to use those parts, so maybe now the latest version has fantastic support and I'm talking nonsense.

[Rochus]

Thanks. I had a close look at v4, but didn't see a reason to update. Some functions got a bit faster on some architectures, some a bit slower, as usual.