Accuracy of Mini S


I have problems to get accurate readings from the mini S with the ROS-Driver on Ubuntu 16.04.
When we measure the size of a known object in the pointcloud (e.g. an OpenCV-Circle Pattern), the scale of the pointcloud (without any calibration) is off by around 10%.

We are also calibrating the RGB and IR camera which gets the error down but we still are not able to measure objects with nearly the advertised accuracy of +/- 1-3mm @ 1m.

How do you calibrate the cameras and what is your experience with the achievable accuracy?