Nodal Point Offset Accuracy

[BlueprintBen]

We’ve been trying to use the Camera Calibration plugin to determine the nodal offset point of our camera relative to the OptiTrack Cinepuck tracking it, and while the process works for us, the results are never close to production-quality; we always see a significant amount of ‘slippage’ between the virtual and real scenes, particularly at the edge of the camera’s view.

Our Lens Distortion calibration had 0.06px of error, so we feel pretty confident that it’s working OK, but again, the Nodal Point Offset calibration doesn’t get us nearly close enough (though it reports 0.00px of error - I think there’s a bug there in UE). I’ve attached images demonstrating our result’s alignment.

Has anyone successfully calibrated camera tracking with OptiTrack, etc, in UE and gotten results that keep the virtual and real scenes aligned within a few pixels at all times?

Panning from Center to Edge:

Center (OK alignment):

Edge (Not good):

[epartidas]

Hello, I wanted to know if you found something about this as I’m running on the same issue. I have an optitrack system as well and after I calibrate the lens and calculate the nodal offset using the checkerboard with markers I am getting the same results as you. Everything is aligned but if I start to move the camera it shifts just like yours.

I have tried with Aruco markers, multiple times calibrating the nodal offset, sometimes is a bit better but never production quality. Any help or input would be highly appreciated ad we’ve been trying to get up and running a Virtual Production setup with green screen for a few months now.

[BlueprintBen]

One aspect that has resulted in improved accuracy was increasing the size of the visual pattern - we’re now using a much larger board from calib.io:

We’re still sussing out if there’s any further improvements we can make.