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Inconsistent pose matrices using RotationalDeviceTracker

December 22, 2016 - 6:01am #1

Hi,

We're currently facing an issue related to the use of the Rotational Device Tracker, that we use in hand-held mode to query poses from Vuforia when we don't have a tracker. It seemed to work pretty well across multiple devices on both Android and iOS, and we've been feeding our renderer with the pose matrix without any issue.

Recently, though, we've been noticing an issue that affects specific devices, where the pose that we get from the Rotational Device Tracker is different than on most other devices we've been testing that on. Basically, using the pose matrix from the Rotational Device Tracker, our world is rendered upside down, or with a 90° rotation.

The specific devices on which we witnessed the issue are:

    - Samsung Galaxy Tab 10 P605 & T520

    - LG Nexus 5X

So far we couldn't find a way to correct this. We've been using exactly what the Rotational tracker guide specify, which is using the pose that Vuforia gives back for the Rotational Device Tracker directly for rendering:

Quote:

// base device matrix that can be used for rendering (will need to be inverted)

which is consistent with the code we studied in the Android Digital Eyewear sample that you provide. In that specific sample, we noted thought that the AR mode does not show anything without a tracker. As such, we have not been able to confirm that the Vuforia sample that uses a Rotational Device Tracker does not have the same issue (which would confirm that we are missing something on our end).

In light of those findings, I would like to ask a few questions:

    - Is the Rotational Device Tracker supposed to be used for AR, and ready to be used for AR?

    - Could there be an issue related to specific devices sensors that would return rotated pose matrices (with a very distinguishable 90° or 180° rotation)?

    - Is there any way to get a proper device-agnostic pose matrix thanks to the Vuforia Rotational Device Tracker?

Any help or suggestion would be most welcome!

Thanks.

Jean-Baptiste L.

Inconsistent pose matrices using RotationalDeviceTracker

January 9, 2017 - 11:20am #2

JBL wrote:

- Is the Rotational Device Tracker supposed to be used for AR, and ready to be used for AR?

The Vuforia Device Tracker can be used for AR content, but cannot provide immersive AR experiences due to fundamental limitations with the data that can be gathered from device IMUs. The Device Tracker provides 3DOF pose updates and unregistered AR experiences that are subject to drift, and cannot account for all possible user motions (6DOF).

JBL wrote:

- Could there be an issue related to specific devices sensors that would return rotated pose matrices (with a very distinguishable 90° or 180° rotation)?

- Is there any way to get a proper device-agnostic pose matrix thanks to the Vuforia Rotational Device Tracker?

Are you seeing these effects when running any of our samples with device tracker enabled?

We were also curious if these issues could be related to "Gimbal lock", at least for the 90 degree pitch rotation. With Euler angles rotation clamping down at [180,180] boundaries?

Thanks.

 

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