Using multiple cameras - ju1ce/April-Tag-VR-FullBody-Tracker GitHub Wiki

To use multiple cameras, you just run multiple instances of ATT at the same time!

NOTE: You need some understanding of how ATT works to get multiple cameras working well. Please get single camera tracking working first, use it for a bit, and refine its parameters! You want optimal single camera performance BEFORE connecting a second one!

To be more precise, follow the following order of steps to ensure nothing goes wrong:

  1. Copy the entire ApriltagTrackers folder! This will also copy over all the parameters of the first one. Everything related to second camera will be done in this instance of att.
  2. Open ATT program for second camera, change the camera settings apropriately and do Camera calibration for it. Tracker calibration was copied, so no need to do it again. You also want to change Quad decimate to be apropriate for the second cameras resolution. Other parameters should stay the same as they were for first camera!
  3. Have both ATT instances open and connect them to SteamVR. Put on your headset.
  4. Start detection on Camera 1. Do playspace calibration for Camera 1. Stop detection on Camera 1. (using the 6.Start/Stop button).
  5. Start detection on Camera 2. Do playspace calibration for Camera 2. Stop detection on Camera 2. (using the 6.Start/Stop button).
  6. If you have any other cameras, repeat for each.
  7. Start detection on all cameras.

Tracking should now work using both cameras! However, there will still be some issues you have to solve:

Other features for multiple cameras

  1. Aligning the two playspaces completetely accurately is very hard. When running both cameras, check calibration mode for one of them. Make sure all trackers are seen on all cameras. Check Refine calibration using second camera. Look at how the RGB axis moves in the out window - it should move exactly into the centers of trackers. If one is too high and other is too low, adjust the C value manualy until it aligns. Then uncheck calibration mode.

  2. Since distance from camera is less accurate than left/right up/down position of trackers, this introduces some shaking. You can try setting Depth smoothing to 0.1 or 0.2 to fix this issue.

  3. Some users report Using centers of trackers parameter help with shaking as well. Make sure to use it on either both cameras or none!

Play with Smoothing parameters as well, as you may be able to use less smoothing than before. When you press save in the parameters window, the settings will automaticaly apply to the driver - no need to restart detection, or updating parameters on both instances. You should still have the same parameters on both cameras when you find the optimal ones, to ensure you dont use wrong ones occasionaly.