ArtTracking

Chair for Computer Aided Medical Procedures & Augmented Reality
Lehrstuhl für Informatikanwendungen in der Medizin & Augmented Reality


MICCAI 2009
MICCAI 2009
London UK

CVPR 2009
CVPR 2009
Miami, Florida

ICCV 2009
ICCV 2009
Kyoto, Japan

IPMI 2009
IPMI 2009
Williamsburg, VA

SPIE 2009
SPIE 2009
Lake Buena Vista, Florida

ISBI 2009
ISBI 2009
Boston, Massachusetts

ART Tracking System DTrack

ART tracking of the company Advanced Realtime Tracking (ART) GmbH, Weilheim are used for different tracking and augmented reality systems at the chair. This is a short manual how to set up an ART tracking system. If you're missing important information or if you want share your own experiences with ART tracking, please edit this website.

Setup

  • Usually you need 2 to 4 DTrack(1or2) cameras, 1 tracking PC running the ART tracking software dtrack, different tracking targets and a network to send tracking data to clients processing such data e.g. for AR applications.
  • All cameras have to be connected with the tracking PC with a network cable, a BNC cable for synchronizing the cameras and a power cable.
    • Depending on the particular hardware, the network cables can also be connected with a switch that is connected with the tracking PC.
    • Depending on the particular hardware, the power cables are connected directly with power sockets.
  • Tracking cameras are equipped with an infrared (IR) flash and data acquisition can be synchronized using the BNC cables. It is important to make sure that two cameras facing at each other do not perform flash and image acquisition at the same time, i.e. they have to be connected with different BNC cables. Cameras that do not face at each other should be connected with the same BNC cable.
  • For connecting two cameras with one BNC cable the BNC T-junction can be used. Make sure that at any cable ending of a chain of connected cameras has to be equipped with an BNC terminator resistor in order to send the sync signal back to the tracking PC.
  • Considering your tracking volume, the minimum distance between your cameras and the tracking targets is around 1 meter, the maximum distance is 4 meters.

Software dtrack

  • Never change a dtrack instance, i.e. tracking settings, calibration, network etc. of another active person!
  • The easiest way to create your dtrack instance is to copy a complete existing dtrack instances from another person to your own directories and adjust your new instance according to your requirements.
  • Depending on the quality and size of the markers of the tracking targets you can and should adjust the flash intensity of the cameras (Settings->Cameras). For Instance, small CT Markers with large distance to the cameras require higher flash intensities. Also light conditions in our environment, in particular daylight, may require some adjustment of the flash intensity.
  • For performance reasons, in (setting->tracking) you should only activate those tracking targets that you really want to detect. In your clients, e.g. CAMPAR applications, you have to define an ID for the tracking data of a particular target. This ID is the index of all disabled AND enabled targets in your dtrack instance. So check for the correct ID of a particular target in (setting->tracking->advanced).

Network

  • For the camera network set the IP address to 172.28.0.1 and subnet mask to 255.255.0.0 and leave anything else empty.
  • The tracking clients, e.g. CAMPAR applications, processing ART tracking data send out requests to the user defined IP address of the Tracking PC. For this reason make sure that your LAN network has either a static IP address or a particular IP address is "dynamically" set with DHCP according the MAC address of your tracking PC (check this with your LAN admin). Also an independent network with e.g. only one client connected directly to the tracking PC is possible.

Marker and Tracking Targets

  • Sphere markers are expensive, so take care of them. Never touch such markers with your fingers! Always use cloves or material free of grease, e.g. handkerchief.
  • If you need some, see MarkerKugeln or ask one of your supervisors or dudes always hanging out in the tracking area.
  • If you need a target, ask again those dudes. Maybe there are unused targets around that can be reused or rebuilt.
  • A target should consist of at least 3 markers, however dtrack accepts only targets with 4 or more markers. Talk to your supervisor or those mentioned dudes for the best solution for your particular target and application.

Room Calibration

  • Use the ART room calibration target to calibrate the cameras and define the ART world coordinate system (calibrate->room).
  • Hide all additional markers or targets in the field of view of the cameras. This can be checked with display->monitor.
  • This target set for room calibration is quite expensive, so imediately after you have finished your room calibration put the targets back into the designated box.

Body Calibration

  • A tracking target consisting of several markers is defined as a body in dtrack
  • Go to calibrate->body and calibrate or recalibrate an existing "body". If you need a new "body" go to (setting->tracking->advanced).
  • Hide all additional markers or targets in the field of view of the cameras. This can be checked with display->monitor.
  • When you calibrate your body move it in the area where you want to track it, which is usually in the center of your tracking volume. Make sure that the cameras can see the markers of your tracking target.

Documentation

  • For the complete documentation please log on janus.informatik.tu-muenchen.de and go to /home/shared/public/Software Images/ART.


Edit | Attach | Refresh | Diffs | More | Revision r1.9 - 12 Feb 2008 - 13:06 - ChristophBichlmeier

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