Hi infinyc
Welcome to LuaRT Community.
There is no specific OpenCV bindings for LuaRT.
Any Lua 5.4 OpenCV bindings should work with LuaRT, but sadly there is none too.
OpenCV is a very very big library on it's own and it will need several months of development to write a Lua wrapper.
It's certainly the reason why there is no modules wrapping OpenCV at this time of writing.