Calibration Overview

Calibration is critical to setting up your PPT system, and without a valid calibration, you will not be able to capture 3D data. Calibrating your system is quick and takes no more than a few minutes for standard configurations. An existing calibration can be invalidated by moving any one of your PPT cameras by even the slightest amount. If you are not certain if your cameras have not been moved or jostled, then it is imperative that you re-calibrate.

After calibrating your system, you will suddenly see your workspace appear on the 3D View. The location and orientation of each PPT camera will be revealed, as will the location and traces for any tracked PPT markers.

The goal of calibrating is to teach your system where each of the cameras is located in your workspace. All you have to do is allow each camera to see the supplied PPT calibration rig - your system will compute the camera's exact position and orientation based on the blink pattern provided by the calibration rig. The calibration process can take as little as 2 minutes to complete.

In a typical calibration, you place the PPT calibration rig on the floor at a location where all cameras can see it simultaneously. The calibration rig is marked with a +X and a +Z direction. You should align these axes so that PPT's coordinate system is oriented in the way you desire. You then run the calibration wizard and within a minute all the cameras are calibrated. Your system's (0,0,0) origin and the forward-up vector is established by the position and orientation of the PPT calibration rig during calibration.

In a more complicated calibration, you might have a physical workspace where not all cameras can see the calibration rig simultaneously (e.g., the room is L-shaped). In this case, you use the calibration wizard to successively capture views of the calibration rig until all cameras have seen it. Your PPT will then automatically chain all these independent calibrations together and form a single reference frame, setting its origin and orientation at the first location of the calibration rig.

Projection VR and coordinate system

Orient the calibration rig so the +Z direction is facing towards the front wall.