Calibrating the cameras

There are three cameras: the webcams (labelled 1 and 2) and the ZED camera. The webcams are calibrated using the launch file calibrate.launch. The ZED camera is calibrated using the calibration utility from the ZED SDK.

The calibration parameters for the webcams are stored in the folder spear_rover/calibration. When launching the webcam nodes with usb_cam, these parameters can be loaded by setting cam_info_url to e.g. file://$(find spear_rover)/calibration/webcam1.yaml for webcam1. Unfortunately, the ZED camera doesn't have an equivalent way to load parameters like this. So the parameters are stored on the tx2, which means that if the tx2 is reset or something we will have to redo calibration.