Flip,

I have never called opencv routines from Mathematica but I think it would not be hard to use Mathematica's WSTP interface to call opencv routines. I would suggest not trying to reverse engineer and use the ones built in to Mathematica because they may not be complete and every time Mathematica upgrades, it will likely break your code. I suggest you install a fresh copy of OpenCv and use WSTP as a robust way to call functions in libraries (or compiled standalone code). Are you familiar with it? If not, here are some documentation links:

This is a good overview of WSTP

This is the full documentation. This is a more detailed overview which includes two sections -- one for MacOS and one for Windows

The included example code is particularly useful.

You can take an image, call an opencv routine and get the results back and continue in Mathematica. I have some more Mac-specific advice on calling library routines (I have done this), Are you using a Mac?

I hope this helps.

Regards,

Neil