About the Vicon calibration device
- Gisela Roberts
- Ben Stanley
You use the Vicon calibration device (Active Wand) to calibrate both optical and reference video cameras in your Vicon system. Calibration enables the Vicon optical cameras to capture the subject's movements throughout the volume. You use the Active Wand in your capture volume to identify the volume origin and axes, so the virtual cameras and volume in your Vicon application software reflect the positions of the cameras in relation to the capture volume and to one another.
The Active Wand is an electronic motion capture calibration device that contains five pairs of LEDs, as shown in the following illustration and described in the table below.
| Key | Part | Description |
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Pairs of LEDs | Used to calibrate both optical and reference video cameras. As some reference video cameras do not have strobes, these LEDs make it easier to identify and locate markers from reference video images. |
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On/Off switch | Power switch |
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LED mode switch | Changes between Strobe and Continuous mode. Use Strobe mode whenever possible. In some cases, Continuous mode may give better results (see the Active Wand User Guide PDF). |
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Intensity adjustment screw | Changes the brightness of the LEDs. |
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Battery charge indicator LEDs | Indicates the amount of charge left in the battery. |
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Bubble level | When adjusting the feet, check the bubbles to ensure device is flat on the floor. |
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Battery charger connection | Charge the battery by plugging the supplied Active Wand charger into this socket. |
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Camera strobe sensor | A photodiode detects the strobes from the cameras, enabling the Active Wand to synchronize to the cameras. |
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NIR On/Off switch | Turn on/off the NIR LEDs on NIR wands, or IR LEDs on IR wands. |
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Adjustable feet | Position the wand flat on the floor when setting the volume origin by turning the adjuster screw for each foot. |
In addition to the above features, the following features are also available, but are not illustrated:
- Handle: Hold this end when performing a wand wave. Also contains the battery. For information on charging and replacing the battery, see the Active Wand User Guide PDF, which is available from the Vicon website.
- Pivot screw (center underside): Align the adjustable feet with this fixed point when setting the volume origin. To enable the Active Wand to lie level, you may need to change the position of the pivot screw from the default position to the alternative position on the wand's arm.
- Force plate alignment guides (can be fitted along the lengths of the wand): If you are placing the wand at the global origin while setting the volume origin, screw each alignment plate into the relevant set of holes and align the guides with the edge of a force plate.
This single calibration device is used for both dynamic calibration and setting the volume origin, as described in Calibration process.
For further details about the Active Wand, see the Active Wand User Guide PDF, which is available from the Vicon website.
The Active Wand is the instrument used to define system accuracy. To ensure continued accuracy, please take care of it and store it safely in its original packaging when not in use.
