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Extended Tracking Best Practices

August 15, 2014 - 1:40am #1

Hello,

first of all, apologizes in case I'm posting this in the wrong section of the forum

We are developing a retail augmented reality application, which relies heavily on extended tracking to allow users to position 3D objects in a room at a life-size scale. (Experience starts from a predefined image target).

The application targets iOS 7 iPad only, and uses the Unity extention.

I would like to know if there are any best practices or ways to use the extended tracking feature in the most reliable / robust way possible, and in particular:

- I noticed a drift in camera tracking and scale when moving the device away from the image target

- If the app includes high-poly objects, will it significantly affect the performance of tracking?

- In your opinion, is the "persistent tracking” feature a good option in a scenario where the user is moving a way from the image target considerably, and even turning the device around the room ~360 degree?

- Are the focus and quality options for the camera affecting the extended tracking?

Thank you very much,

Andrea

Extended Tracking Best Practices

August 17, 2014 - 12:10pm #2

- I noticed a drift in camera tracking and scale when moving the device away from the image target

Try activating the persistent mode of Extended Tracking  - https://developer.vuforia.com/resources/dev-guide/extended-tracking - this is recommended for scenarios that need to accommodate a lot of movement by the user and extended distances.

- If the app includes high-poly objects, will it significantly affect the performance of tracking?

Very complex models may affect tracking performance due to their impact on runtime resources. Try evaluating a simpler model to determine if this is a factor for your app. 

- In your opinion, is the "persistent tracking” feature a good option in a scenario where the user is moving a way from the image target considerably, and even turning the device around the room ~360 degree?

Yes, though Extended Tracking isn't intended to support panoramic views. You'll need to evaluate its performance with the persistent mode activated. You can also try placing additional targets as these will help to anchor the coordinate space. 

- Are the focus and quality options for the camera affecting the extended tracking?

Focus certainly helps, try an autofocus setting if you find that your app is losing focus on the subject matter of your scene. 

The camera modes are used to privilege frame rate vs render quality. Setting MODE_OPTIMIZE_SPEED can provide more camera frames for Extended Tracking to work with. 

 

Extended Tracking relies on the same sorts of features that Vuforia targets do. These are captured from the environment at runtime. For the best user experience, both the target and setting should remain stable. Moving the target will corrupt Extended Tracking and introducing non-target objects to the setting after Extended Tracking has been activated can result in the same. Also the target should be on the same plane as its background (e.g. on a floor, table top, or wall ). 

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