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In order to use LPVR-DUO we need to connect the various parts and we need to calibrate the orientation of the reference IMU that is mounted to the vehicle. For the following settings we give the line numbers in the default configuration.
- in
In order to receive data from DTrack the port number configured on line 7 needs to match the one configured in DTrack. The default configuration uses port number 5000 which is also the default for DTrack.
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In DTrack’s Output Settings you need to set one channel to “active” and configure it to send to “this computer” with at least “ts” and “6d” output enabled. Depending on your firewall settings you may have to select “act as router for tracking output”.
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You also need to configure the correct body ID for the tracked body associated with the headset. This number goes on line 42 of the configuration.
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Lastly, for the purpose of calibration, we also need a tracking body attached to the reference IMU. Its tracking body ID goes on line 69.
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Once these settings are complete, click the button labelled “Push To Driver” above the input field. The driver should now have adopted the settings.
If you have already calibrated the headset tracking body (see above), you should now be able to now use the headset with DTrack tracking. It should also react to motion of the reference IMU. Though as long as the reference IMU is not calibrated, this motion should not make much sense.
Validation Steps
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After this basic configuration all necessary data should be flowing and available to Varjo Base. We suggest to take a few minutes to make sure this is the case. Namely, at this point the headset motion should be picked up by DTrack, IMU data should be flowing and the driver should receive these data and provide a an (uncalibrated) synthesis to Varjo Base.
In particular the following items can be verified:
DTrack tracking works
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- Make sure that the headset is tracked by DTrack
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. DTrack should be running and the DTrack software should show it’s body number on a green background
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All required data reaches the driver
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- After clicking “Show details” near driver status on the configuration page, all sources (DTrack, HMD Imu, Platform Imu) should be displayed in green as shown below.
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Some troubleshooting suggestions:
If the DTrack indicator is not green make sure that DTrack is running and that the Output settings in DTrack and the port number configured for the LPVR driver are correct and agree.
- if the Platform
If the indicator for the platform IMU is red, make sure its USB cable is connected and restart Varjo Base. We discuss its setup in detail further down.
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If the
Headsetheadset IMU indicator is red, please restart Varjo Base. If it remains red, please make sure
theVarjo Base
displays no errors The headset reacts to rotations: stop the DTrack measurement. The VR scene shoudl move along with rotations of the headset.
Positional data is transferred correctly: start the DTrack measurement again. Moving the headset without rotation yields the expected motion.
Headset body calibrated: if the headset body is already calibrated, rotations of the headset should appear smooth.
Platform Imu data is received and incorporated: rotating the Platform IMU leads to a response in the VR scene. Before calibration rotation axes may not match. This will be addressed in the next steps.doesn’t display any errors.
Adjustment of Vehicle Fixed IMU
Follow this tutorial to install and run the vehicle-fixed LPMS-IG1 IMU. If you are using LPVR-DUO -for Varjo with the ART SmartTrack and our provided IMU holder, you should be done at this step. If you are using another setup, please follow the steps below.
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Fix the reference IMU to the vehicle in the intended location with the optical marker still attached. Make sure that it is visible to DTrack. We now need to read the orientation quaternion from Varjo Bases log files and enter them as
referenceOrientationQuataround line 59 of the configuration. Accessing the Varjo Base log files takes a few steps which we detail below.Open Diagnostics from the Support menu in Varjo Base
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On the next screen, click Start
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Click “Skip” in order to not record eye tracking data
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You are now presented with the following screen which provides you with a link to the location where the log files are stored. Click on “Show folder”
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Enter the log folder, out of the files named
tracking_<number>.logselect the latest one and open it.Near its end search for lines similar to this
20210120 15:16:31.156 --- [Varjo::Tracking::PluginUtilityAPI::WriteLogMessage] PLUGIN: [INFO] new pose: q = {"w":0.9913584114738726,"x":0.1302836073262127,"y":0.006246731684853627,"z":-0.013979051208529776} pos = {"x":-1.1893610000000001,"y":0.831757,"z":-0.936706}Replace the contents of
referenceOrientationQuatin the configuration web page with the values ofqin the log file, i.e.{"w":0.9913584114738726,"x":0.1302836073262127,"y":0.006246731684853627,"z":-0.013979051208529776}in this example.After the above procedure the optical marker can be detached from the reference IMU.
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