I've done iRVision robot-generated calibration at a height of 55 mm of the workplace height with a printed target on an EOAT. The camera we use is a 1.3 MP camera at a height of around 500 mm. We're not getting accurate measurements, with measurements ranging from 1 to 2 mm off for X and 2-4 mm in Y.
I tried measuring at the level of calibration, and the measurement was still off by around 1 mm. The measurement is at around 450 mm from the camera.
Just wondering why. I was thinking it might be the focus of the camera