Mixed reality camera calibration

XR-1 Developer Edition

Every Varjo headset is precisely calibrated during manufacturing. As high-precision optical instruments, the mixed reality cameras on your headset can be affected by improper handling.

In some rare cases, such as if the headset is dropped, you may need to recalibrate the cameras on your headset. Please note that we strongly recommend recalibrating your cameras only if the current calibration settings are clearly flawed.

 

 

Testing the mixed reality camera calibration

XR-1 Developer Edition features video pass-through and infrared cameras. Varjo provides example programs to help you verify that the cameras on your headset are calibrated correctly.

Please follow the instructions below to test the camera calibration of your headset.

 

 

Setting up the example programs

  1. Download and install Varjo Base.
  2. Download Varjo SDK for Custom Engines.
  3. Build both the MarkerExample and MRExample programs included in the examples folder in Varjo SDK according to the instructions in varjo-sdkexamplesREADME.txt.

Please note that you should build the example programs using the Release configuration in CMake.

  • When using CMake from the command line:   > cmake --build . --config Release
  • When using the Visual Studio IDE, choose the Release configuration in the Configuration Manager.

 

 

Testing video pass-through camera calibration

  1. Print a Varjo Marker in medium size. Please follow the instructions carefully and make sure that the marker is sized correctly.
  2. Run Varjo Base and MarkerExample.
  3. Pointing your headset at the marker, observe if the rendered marker lines up with the physical marker. You can do this either in the Analytics window in Varjo Base or while wearing the headset. For easier inspection, open a magnified view in the Analytics window and select the Left, Right, and Focus options in the toolbar.

 

The image shows examples of marker alignment in the headset view. The right view in the top row shows the rendered marker offset from the physical marker. In the second row the markers are correctly aligned.

If your headset displays misaligned markers, you may need to recalibrate the cameras. Please follow the instructions to recalibrate.

 

 

Testing infrared camera calibration

  1. Run Varjo Base and MRExample.
  2. Press F7 in the console window to turn on depth estimation.
  3. Several cubes will be visible in the headset view. Moving your hand in front of the cubes, observe if your hand occludes the cubes correctly. We recommend wearing your headset while doing this, although you can also use the Analytics window in Varjo Base.

 

The image shows examples of hand occlusion in the headset view. On the left the hand mask is offset from its correct location, which may cause the background to be visible through the cube. On the right the hand mask effect matches the location of the real hand.

If the hand mask does not line up with the real location of your hand, you may need to recalibrate the cameras on your headset. Please follow the instructions to recalibrate.

 

 

Recalibrating the mixed reality cameras

The cameras on your headset can be recalibrated in Varjo Base using a camera calibration marker available from Varjo. You can request a calibration marker through Varjo Support.

Under the Support tab in Varjo Base, select Recalibrate mixed reality cameras to start recalibration. Holding the headset in your hands, place the camera calibration marker in view of the front-facing cameras and follow the instructions. Please make sure to have good lighting in the room when calibrating.

To verify the results of recalibration, please follow the instructions to test the calibration of the mixed reality cameras.

You can reset your calibration settings to the factory defaults by clicking on Reset to factory calibration settings. This option becomes available after you have manually recalibrated the cameras.