Been reading about "Virtual Visual Servoing" http://rainbow-doc.irisa.fr/pdf/2002_eurographics_marchand.pdf -- maybe the most convoluted way to explain a smoothing/filtering algorithm (?) that I've seen lol
(it's mentioned in https://github.com/Jcparkyn/dpoint as part of their pipeline, how they postprocess the camera tag detection, although if you look at the source code they pretty much just call an OpenCV function https://github.com/Jcparkyn/dpoint/blob/a108c19b9b240c1531b2d30ed47ba18bc604862e/python/app/marker_tracker.py#L166)
The survey paper that they did 14 years later https://inria.hal.science/hal-01246370v1/document completely drops the "visual servoing" metaphor/terminology and explains it purely as a computation -- you have to dig into the citations to figure out that they're talking about VVS here