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3D scene drifting from target on certain (android) devices

August 1, 2018 - 9:10am #1

hey there,

I use Unity 2017.4.6 / Vuforia 7.0.57. After my last tests, some months ago, I'm happy to see, that cloud tracking now works on android / editor as expected. But now I face another strange bug: my testdevice is a samsung s7 (which is in my eyes quite common) and I wondered about a strange drift of the 3D scene from the marker... this was not visible in editor. So I installed it on my Moto Z and... it worked. I created a video for better understanding:

https://youtu.be/lsYJOGyrnXQ

In this case I use a cloud target, but I tested also image targets (on device) and there it's the same problem. Both devices use the same app version.

Maybe in some apps the drift is not so visible, but in my case I put buildings on ground planes and this should be accurate.

Does anyone experienced this bug or have some ideas for a workaround?

For me it seems like a wrong calculation from the android camera aspect /fov - something like that.

I hope the solution isn't again to update unity + vuforia, because everytime I do this, I takes some time to get all things working again and and some point I find a new bug ;) - I like the idea of the LTS support of 2017.4 and really hope to get the app working on a stable version / code base.

best regards

Simeon

 

 

3D scene drifting from target on certain (android) devices

August 16, 2018 - 9:34am #5

Yes, that's the correct summary.

3D scene drifting from target on certain (android) devices

August 8, 2018 - 12:16pm #4

Hello,

Thanks for the additional details. To clarify, here's my understanding of what you've seen:

  • In Unity 2017.4.6 / Vuforia 7.0.57, you've observed tracking drift when using the S7. Assumption is that this was due of the introduction of VIO-based Extended Tracking which is automatically enabled by Vuforia
  • In Unity 2018.2.2 / Vuforia 7.2.24, you've observed tracking drift when using the S7. This is seen when enabling Fusion via APIs for both SLAM-based (legacy) and VIO-based Extended Tracking

Is the above an accurate summary? Just want to make sure I have the details correct before investigating further.

Thanks,

Vuforia Engine Support

3D scene drifting from target on certain (android) devices

August 8, 2018 - 8:46am #3

Thank your for your information about fusion and tracking provider. I installed Unity 2018.2.2 and upgraded to Vuforia 7.2.24.

First I tried, if maybe the bug is solved on the S7 without changing the provider, but it's the same drift when using the VUFORIA_SENSO_FUSION. I check the provider simply by starting a coroutine and log the print "VuforiaRuntimeUtilities.GetActiveFusionProvider()" to the log after 5 seconds.

Then I switched to the recommend old tracking via VuforiaRuntimeUtilities.SetAllowedFusionProviders (FusionProviderType.VUFORIA_VISION_ONLY). My check above also confirms, that the app now uses this tracking provider. BUT the problem/bug still consists and looks same way wrong as seen in my video.

I'm pretty sure that this is a more complex problem. Would be great, if we can investigate this further, in never recognized such inaccuracy in older versions of vuforia. I'm also pretty sure that even the new VIO based tracking shouldn't have such a big drift while the image tracker is present.

3D scene drifting from target on certain (android) devices

August 2, 2018 - 1:16pm #2

Hello,

What you're observing is performance differences between VIO-based Extended Tracking (rolled out in SDK 7.0 as part of the Vuforia Fusion feature) and SLAM-based Extended Tracking. The Moto Z does not support VIO-based Extended Tracking, the Samsung S7 does (by default).

One of the drawbacks of VIO is that accuracy can suffer with gyro drift. However, it can also outperform SLAM in challenging visual environments.

Unfortunately, the answer is related to upgrading to SDK 7.2. In this release, we have exposed APIs that allow developers to choose between the two different Extended Tracking technologies, depending upon the use case (see the "Fusion APIs" section of the aforementioned article). These APIs do not exist in the 7.0 SDK release.

Thanks,

Vuforia Engine Support

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