vicon tracker

1. Vicon Tracker

Vicon Tracker - ©Vicon Motion Systems Ltd. UK
Vicon Tracker is a powerful object tracking solution providing unrivaled data accuracy for integration in to 3D applications such as VirTools, Labview, Open Scene Graph, WorldViz, Panda3D and VR Juggler. Tracker has been designed for applications as diverse as robot tracking, ingress/egress, human factors engineering; design method optimization, virtual engineering and previzualization.

2. Usage in the lab

Ten Bonitas have been installed in our TMS demo space. They caputure the positions of markers; infrared reflector, that enables us to utilize the geometric information of the objects.

• SmartPal 4
• SmartPal 5
• Quadcopter
• Glasses
• Oculus Rift

3. Calibration

The system requires calibration on a regular basis. The calibration consists of two separate tasks, working in a measured space and checking the progress on the Vicon Tracker; preferably done by two people. Do not change the parameters of "SETTING" in "SYSTEM" tab.

3.1 The Active Wand

The Active Wand - ©Vicon Motion Systems Ltd. UK
The Active Wand is Vicon’s Dynamic Calibration device. Its active markers calibrate both optical and video reference cameras with unparalleled accuracy.

3.2 Camera calibration

Calibration procedure is as follows.

1. Switch the right pane to CAMERA-view.
2. In "SYSTEM" tab, select all items of "VICON CAMERAS" to enable to check all the cameras.
3. At the top of "CALIBRATE" tab, Set "WAND:" and "L-FRAME:".
   • WAND: Active Wand
   • L-FRAME: Active Wand Original
4. Click "START" at the "CARIBRATE CAMERAS" to start calibrating.
5. Walk around in the demo space, waving the wand irregularly. You can see rainbow trails on the right pane.
6. Meanwhile, check the progress at the "CAMERA CALIBRATION FEEDBACK". Its colours represent pixel errors.
7. When all the colours have changed to green and the rainbows have disappeared, calibration is complete.

3.3 Masking

Reflection objects and other camera's glare can be noises. Thus, the system needs to set the mask and eliminate initial noises.
Before masking, remove any reflectors from TMS demo space, including objects to track on Vicon.

1. Switch the right pane to CAMERA-view.
2. Uncheck all items in "VIEW".
3. In "CALIBRATE" tab, click "START" at the "CREATE CAMETA MASKS". Masking automatically progresses.

Using the some buttons at the top of the right pane, you can set the mask on noises to eliminate manually.

3.4 Set the origin

The wand can indicates origin of the world coordinates. Place it in the demo space to set the origin.

1. Click "START" at the "SET VOLUME ORIGIN".
2. Place the wand properly. Adjust the Wand's origin to particular point; x=2000[mm], y=500[mm].
3. And click "SET ORIGIN".

4. Creating skelton models

4.1 Preparing the objects

Attach three or more markers to actual objects.

4.2 Putting the objects

Set the marker-attached objects in the measured space. Object coordinates are configured, based on the world coordinates. Thus, you shoud set them in accordance with the grid of carpets. Refer to this figure to check the axis of coordinates.

Meanwhile, you can confirm that the reflective markers appear on the right pane.

4.3 Creating skelton models

Select appropriate markers and create tracked models on Vicon Tracker.

1. Make sure that the markers of objects you set appears on screen.
2. In "OBJECTS" tab, click the stop icon to pause cameras.
3. Select appropriate markers by right click.
4. At the bottom of the tab, fill in the "CREATE OBJECT:" with name.
5. Click "CREATE".

4.4 Editting the models

• Changing the name
  In "OBJECTS" tab, click the drop-down menu; "▼"-like button.

• Editting the origin
  The default origin is center of all markers. To change the origin of coordinates, drag the axis by left click. If making some markers active in advance, you can move the coordinates in accordance with the grid.

The objects you creates are managed as .vsk files; vsk stands for "vicon skelton".

5. Usage of data

Make sure that vicon_stream and tms_db_writer are active.

rosrun tms_ss_vicon vicon_stream  

roslaunch tms_db_manager tms_db_manager.launch

The data acquired from Vicon system are published to the ROS topic, and written to database one after another.

Topic /tms_db_data

Type: tms_msg_db/TmsdbStamped  
  
Publishers:  
 * /vicon_stream  
  
Subscribers:  
  /tms_db_writer  

Request /tms_db_reader/dbreader to get the information.