Log in or register to post comments

Uncertainty Extended Tracking in HoloLens

July 8, 2019 - 3:14pm #1

Hello,

I have 4 Question, which I would like to hear the answer or an approval for my through about this topic.

I have an image target and the option Track Device Pose is not activated. Currently when the image targe is not in fov, the ar content still appear. That is what I aim for. 

1. So according to the information from here. From my understanding,even when I do not activate the Track Device Pose, HoloLens still use its own spatial mapping to track the pose of the ar content right ? (therefore I could see the ar content even when the image target is out of view)

2. What I really dont lilke is that the ar content is very lag. The gaze of hololens is not smooth when I aim to the ar content. is it because of the hololens hardware or because of spatial mapping in hololens?

What I discovered so far:

3. Ar Content appeared even when image target not in fov, but the ar camera still  turn on? Why and could I disable without problem to reduce the workload ?

4. So in conclusion: Especially in HoloLens you dont need to activate Track Device Pose from Unity, the extended Tracking behaviour is automatic set when you developt app under HoloLens ? If its like that, so currently I can see that HoloLens use spatial mapping to track and the ar camera also turn on, which mean vuforia also use extended tracking.

 

What I really want:

irrespective of whether extended tracking by vuforia or spatial mapping by hololens, the arcontent should still present when the image target is no longer in the field of view. If spatial mapping is used then the AR-Camera should be switched off to prevent the exposure. Conversely, if spatial mapping is not used by HoloLens, then vuforia should  enable Extended Tracking and only Extended Tracking will be applied.

 

Thanks

Uncertainty Extended Tracking in HoloLens

July 15, 2019 - 3:49pm #2

Hello,

quangbui wrote:

1. So according to the information from here. From my understanding,even when I do not activate the Track Device Pose, HoloLens still use its own spatial mapping to track the pose of the ar content right ? (therefore I could see the ar content even when the image target is out of view)

"For HoloLens applications, the Positional Device Tracker needs to be started for every app and is automatically started in Unity." Therefore, you only need to enable the Positional Device Tracker if you are developing for native UWP.

When the Positional Device Tracker is enabled, HoloLens spacial mapping is used to track the target. However, if the target is in the HoloLens' web camera's field of view and it moves from the original detection position, Vuforia Engine will update the pose.

quangbui wrote:

2. What I really dont lilke is that the ar content is very lag. The gaze of hololens is not smooth when I aim to the ar content. is it because of the hololens hardware or because of spatial mapping in hololens?

It is VERY important to keep the Model and rendering complexity to as low as possible, so to guarantee a constant/stable 60 FPS rendering, which seems to be crucial to minimize wobbling/shaking/jitter. Some ways to optimize this are:

  • Keep model triangle count well below 100K triangles (prefearrably under 50K triangles)
  • Set the light settings to "Mixed" or "Baked" (do not use "Realtime")
  • Use simple shaders (e.g. "Mobile/VertexLit" for example)
  • Enable "Depth Buffer Sharing Enabled" setting

quangbui wrote:

irrespective of whether extended tracking by vuforia or spatial mapping by hololens, the arcontent should still present when the image target is no longer in the field of view. If spatial mapping is used then the AR-Camera should be switched off to prevent the exposure. Conversely, if spatial mapping is not used by HoloLens, then vuforia should  enable Extended Tracking and only Extended Tracking will be applied.

In Unity, you can fix a trackable in space after detection by detaching the augmentation from its parent trackable with Transform.setParent(null, true);. The drawback to both is that your augmentation will no longer update its pose, so alignment usually goes slightly off as one moves around the target.

Thanks,

Vuforia Engine Support

Log in or register to post comments