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On the Calibrate tab, in the Calibrate Cameras section, you can change the following settings:

ControlDescription
WandCalibration object to be used during the camera calibration process.
Calibration TypeThe level of camera calibration to be performed when the camera calibration process is started:
  • Full Calibration A full camera calibration process enables the Vicon system to determine each camera's physical position and orientation in the capture volume and to correct for any lens distortions, and to set internal camera parameters. You must perform a full camera calibration when the system is first installed and set up or if your camera setup has changed significantly.
  • Calibration Refinement A camera calibration refinement process enables you to correct a simple problem with a camera calibration. The Vicon system recalculates the previous calibration data based on the current location of the cameras. You can refine an existing calibration only if the camera positions have not changed significantly.
For more information about calibration types, see Understanding calibration types below.
Cameras To CalibrateA list of cameras to be included in the camera calibration process. Cameras not included in this list are not calibrated. If this field is blank, all cameras are calibrated. The selection of cameras is applied when you click the Stop button in the Calibrate Cameras section.
Refinement FramesWith auto stop selected, the minimum coverage (in number of frames) required per camera in the final phase of refining a camera calibration.
Wand Ratio ToleranceTolerance of the distance between the markers on the wand (expressed as a ratio), to enable it to be labeled in 2D. Default is 0.2.
Wand Straightness ToleranceTolerance in alignment of wand markers (relating to the maximum angle allowed between markers) to enable it to be labeled in 2D.
Auto StopWhether or not Tracker is to automatically stop the camera calibration process when sufficient data has been collected.

Understanding calibration types

Full Calibration consists of an initialization phase, followed by a multi-pass process to optimize the camera positions.

Calibration Refinement uses exactly the same process as full calibration, but without the initialization phase. It provides a reliable way to refine existing calibration data to produce a calibration that is as good as a full calibration of the same system, but is much faster.

Because Calibration Refinement operates on existing data, you must have loaded a full calibration into Tracker before running the refinement calibration.

To save time while maintaining accuracy, you can perform both full and refinement calibration on any selected camera(s), as well as on all cameras.

Note that the value specified for Refinement Frames affects the number of frames used:

  • By Auto Stop
  • In the refinement phase of a Full Calibration
  • When running a Calibration Refinement

The following table gives examples of using each type of calibration:

ScenarioType of calibration
A full calibration of all cameras has recently been performed, but since then, several cameras have been repositioned to another part of the volume.Full Calibration on just the moved cameras, with a short wand wave that concentrates on the moved cameras,
A full calibration of all cameras has recently been performed, but during capture, one camera was accidentally slightly bumped. Full Calibration on the bumped camera, with a short wand wave that concentrates on the bumped camera.
Since yesterday's full calibration, environmental factors may have caused small changes in the camera positions and it is necessary to re-calibrate them accurately and quickly.Calibration Refinement of all cameras, with a normal length wand wave that includes all cameras.