When capturing throughout a whole day, temperature fluctuations may degrade calibration quality and you will want to recalibrate the capture volume at different times of the day. However, repeating entire calibration process could be tedious and time-consuming especially with a high camera count setup. In this case, instead of repeating the entire calibration process, you can just record Takes with the wand waves and the calibration square, and use the take to re-calibrate the volume in the post-processing. This offline calibration can save calibration calculation time on the capture day because you can process the recorded wanding take in the post-processing instead. Also, the users can inspect the collected capture data and decide to re-calibrate the recorded Take only when any signs of degraded calibration quality is seen from the captures.
Offline Calibration Steps
1) Capture wanding/ground plane takes. At different times of the day, record wanding Takes that closely resembles the calibration wanding process. Also record corresponding ground plane Takes with calibration square set in the volume for defining the ground plane.
Whenever a system is calibrated, a Calibration Wanding file gets saved and it could be used to reproduce the calibration file through the offline calibration process
2) Load the recorded Wanding Take. If you wish to re-calibrate the cameras for captured Takes during playback, load the wanding take that was recorded around the same time.
3) Motive: Calibration pane. In the Edit mode, press Start Wanding. The wanding samples from recorded 2D data will be loaded.
4) Motive: Calibration pane. Press Calculate, and wait until the calculation process is complete.
5) Motive: Calibration pane. Apply Result and export the calibration file. File tab → Export Camera Calibration.
6) Load the recorded Ground Plane Take.
7) Open the saved calibration file. With the Ground Plane Take loaded in Motive, open the exported calibration file, and the saved camera calibration will be applied to the ground plane take.
8) Motive: Perspective View. From 2D data of the Ground Plane Take, select the calibration square markers.
9) Motive: Calibration pane: Ground Plane. Set the Ground plane.
10) Motive: Perspective View. Switch back to the Live mode. The recorded Take is now re-calibrated.
