Object jitter/disappear when extended tracking is ON

Hi vuforia, I am new to AR, I make a simple scene with Image Target which is only parent some cubes to Image Target, that's all, my Image Target, a butterfly, is rated 5 stars.

I run my app on iphone 6s, I did following:
1. Turn on Device Tracking -> ROTATIONAL -> handheld -> Enable prediction.
2. Turn on Extended Tracking on image target.

What happen:
1. I use my ipad mini2 to show my butterfly (image target), I place my tab on bed. I have good lit environment. My object show a little bit jittering when the target still shown in camera, the jitter disappear only when my iphone is very close to my tab which is around 30cm.
2. When I start to move my iphone up and pan my iphone, just after the target is out of my view, everything start to jittering, and the jitter amplitude increase, also their scale, position,rotation changes, looks like the world matrix never correct after the target is missing, sometimes everything disappear.

Since I check many videos about extended tracking on youtube, it seems that some guy don't have these problem, I don't know if my operation is incorrect, please help me to figure out, thanks a lot, I use Unity 2017.2.0f3.

 

Hello @yjcnbnbnb200

I did some testing with the iPhone 6s and wasn't seeing jitter when using the settings you described.

Is the target you're looking at 30cm, or are you holding the phone 30cm from the target? Is there any reflection in the surface of the iPad you are displaying the target on?

Thanks

 

Yep, since I didn't have a printer, I use pad to show target image, so sometimes the reflection from surface will affect as you said, and I did look at distance around 30cm, another thing I concern is if DEVICE ROTATION TRACKING supported with iphone 6s, because with extended tracking method on, how can vuforia detected my phone moving uo and down?

 

Device Rotation Tracking is supported with iPhone 6s, but it likely isn't having any affect on the use case you are describing of straight Image Target detection. The Extended Tracking field will handle your phone moving up and down in relation to the image target.

I'd recommend disabling the rotational tracking and finding a way to print out your target, or find a target not on a tablet's screen to use.

 

Really thanks for your advice! Can't wait for vuforia version 7!