...
To calibrate your Vicon cameras, complete these procedures listed in this order:page in the order they appear.
| Scroll only | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ||||||||||||||||
| |
...
- At the top of the Camera Calibration tab, in the Wand list, ensure the option for the type of wand that you are using is selected (this will normally be one of the Active Wand options).
- To start collecting wand data, click Start Wave.
The button displays Stop Wave and in the menu bar, the text Camera Calibration Active is displayed, next to a flashing red circle. Have someone wave the wand throughout the capture volume, covering depth as well as height, while you watch the Cameras views for all cameras to ensure you get full coverage. Ensure that the markers (LEDs) on the wand remain visible to all the cameras as much as possible while the wand is moved throughout the volume.
As an indication that sufficient wand wave data has been collected for a particular camera, the display in the each view changes from orange to blue.
Scroll pagebreak - In the table in the bottom half of the Camera Calibration tab, notice that the Wand Count column changes from red to green as sufficient data per camera is captured. This helps you concentrate on waving the wand for cameras that need more data.
Tip: By default, camera calibration stops automatically when each camera has seen enough of the wand to ensure calibration. To adjust this or turn it off, at the top right of the Camera Calibration tab, click Show Advanced and then click the ellipsis (…) to the right of the Start Wave button. - In the Image Error column, in addition to displaying the values, Shogun Live grades the status of each camera between red (poor) and green (excellent), depending on how much the cameras see the wand.
In the volume, the display on Vicon optical cameras changes to indicate their calibration status:- Vantage, Vero, Viper and ViperX cameras: The status lights turn magenta and blink during calibration, becoming green and then blue when fully calibrated. On the OLED display (Vantage cameras only), a pie chart indicates the fraction of the required wand data that has been received from the camera.
- MX T-Series cameras: The status light on the front blink while you are performing the wand wave, and then go solid blue when enough data has been collected to calibrate the camera.
When enough data has been collected, Shogun Live starts processing the wand wave data. Depending on the number of cameras and the length of your wand wave capture, this may take a few minutes. The progress bar indicates the calibration progress, and table below indicates the calibration results.
Scroll pagebreak In the Log, you are warned if your wand wave has insufficient spread across cameras to give a good calibration. The warning displays both the camera User ID (the number you can provide for the camera in the camera's properties, and URN (the Device ID, found in the camera's Advanced properties).
When the wand wave is finished, an .xcp and an .x2d file is created in C:\ProgramData\Vicon\Calibrations. If your calibration included Vicon video cameras, two x2d files are created. The files are:
LatestCalibration.x2d, which contains the wand wave without any Vicon video cameras
LatestCalibration_withVideo.x2d, which contains the wand wave including Vicon video cameras.
...
After you have captured a wand wave, you set the volume origin and axes so the cameras and volume in Shogun Live reflect the actual positions of the cameras in relation to the capture volume, as well as to each other.
- To enable you to see the axes in relation to the volume, on the Workspace tab, change the view to 3D Scene.
- Place the calibration device on the capture volume floor in the position you want the volume origin to be and in the orientation you want the axes to be (reflected in the axes displayed in the 3D Scene view).
- X: red line
- Y: green line
- Z: blue line
At the top of the Camera Calibration tab, in the Wand list, ensure the appropriate Active Wand is selected.
Tip: If you're working in a Y-up coordinate system, display the Advanced properties and in the Set Volume Origin section, select Legacy Y-Up Scene Orientation.- Click Start Set Origin.
The button displays Set Origin. - After a few seconds, click Set Origin.
- In the 3D Scene, display the View Filters options and under the Volume options, ensure that Cameras is selected.
Scroll pagebreak - In the 3D Scene, Perspective view, all of the cameras shift as a group, so the origin of the capture volume is aligned with the wand.
Scroll pagebreak
| Anchor | ||||
|---|---|---|---|---|
|
Set the origin with a custom L-frame
anchorTo improve calibration stability and consistency over time, you can use a custom L-frame to set the origin of your system.
As described in Set the volume origin, you can use a Vicon Active Wand to set up your volume coordinate system quickly and easily. However, using a larger, custom calibration object (in this case, markers embedded in the volume floor and/or wall) can improve calibration stability and consistency over time.
A typical way to use a custom L-frame would be to keep markers on wall, hidden during camera masking, then when you're ready to set the coordinate system for your volume, make the markers visible and use the custom L-Frame as described below.
See also:
Vicon Shogun 1.3 Live Tutorial - Custom L-Frame Workflow on YouTube.
| Scroll ignore |
|---|
|
To create a custom L-frame:
- With the system calibrated, set the origin as normal (see Set the volume origin), including setting the floor offset (see Set the floor plane), as required.
- Position a number of markers on the edge of the volume and select them.
- On the Tracking tab (right), in the Prop field, enter a name for the custom L-frame and click Create.
The new custom L-frame prop is displayed in the 3D Scene view.
- Pause the real time and in the Tracking panel on the right, select the prop you just created.
- To display the Object Manipulator, press M. (For more information on the Object Manipulator, see Move props.) In the Workspace (3D Scene view), the Object Manipulator is displayed.
Scroll pagebreak - In the Tracking panel on the right, ensure that the custom L-frame is still selected, and with the Object Manipulator set to Global, change all the values to zero, so the origin matches that of the L-frame.
- In the Tracking panel, with the custom L-Frame selected, right-click and then click Export.
- Navigate to Users\Public\Documents\Vicon\CalibrationObjects and click Select Folder. The custom L-frame is automatically saved as a VSK.
Scroll pagebreak
To use the custom L-frame:
- Click Play to resume the real time.
- On the Camera Calibration tab (right), ensure the Advanced options are displayed (if not, click Show Advanced, top right).
- To the right of Start Set Origin, click the button for additional options.
- In the L-Frame list, select the new custom L-frame.
- Click Start Set Origin.
The new custom L-frame is used to set the origin. - When done, click Complete Set Origin.
...
- In the System panel, expand the Video Cameras section and click on one or more video cameras.
The Cameras view displays the video data for the selected video camera(s). - In the Cameras view, click View Filters and in the 3D Data section, select the 3D option.
In the view pane, a 3D overlay is displayed. Because this displays a flat overlay on a 3D Scene, the edges appear distorted. - To remove the distorted appearance, select Distort 3D.
The 3D perspective is flattened to match the video.
- Check that the video of the markers and the 3D perspective line up accurately.
| Tip |
|---|
| Tip To check your calibration, from the View Filters options, select Camera Rays. If you select one or more cameras, this displays lines (rays) to everything the selected camera(s) can see. If you select one or more markers, this option displays lines from all cameras that can see the selected marker(s). |
Your Vicon cameras are now calibrated and ready to capture data.
| Anchor | ||||
|---|---|---|---|---|
|
Adjust the Set Floor Plane settings
...
If you are not using 14 mm markers, to enable you to set the floor plane accurately, click Show Advanced, click the ellipsis next to Start Set Floor Plane, and change the Height offset value to an appropriate value. The Height offset is the amount (in mm) by which to adjust the floor plane (the default is 7 mm). Because Shogun finds the centers of the markers, set a Height offset that accounts for the size of the markers (for example, for 14 mm markers, the Height offset is 7 mm). If the markers include a base, take this into account in your calculations.
...