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5 stars images not correct

September 16, 2015 - 7:42am #1

Vuforia SDK Version: 5.0.5 -

Description with steps to reproduce:

We posted some images and got 5 stars , but real tracking behavior was like a 2 stars or less.

 

1) We were using the demo project changing only the images taken from the online target manager.

2) We were using advanced tracking and best autofocus mode (CameraDevice.FocusMode.FOCUS_MODE_CONTINUOUSAUTO) on unity version.

3) The only way to let the app track the markers was to focus another object and move the camera after to the marker. Placing a hand over the camera worked the same. 

4) We tried with other images with 5 stars too and instead they worked better (we spent over two weeks trying to understand if the culprit was some setting of our project).

 

On Android this behavior this problem less common, on iOS devices was really depending on the device (iphone 4s, 5, 6, ipad 2, ipad air). 

 

We did find incoherence on tracking results depending on device.

 

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Development OS (Mac OS X, Windows, Linux): Mac OS X -

Mobile OS and Version: iOS / Android 8.1.4 -

Mobile Device Manufacturer and Model name: Apple -

Do the Vuforia Sample Applications show the same behavior?: Yeah

5 stars images not correct

September 18, 2015 - 1:23pm #5

1) In the reported images we didn't put any pattern

2) we know about the b&w conversion we use to check tracking points.

3) please tell us why the image isn't tracked property, we already have read those pages tens of times due to our client yielling from all august and september at us because the 5 stars markers don't work as reported by the platform. As you can see we tried tens of variants but tracking works with incostistend results on different devices.

dm3d wrote:

The star rating is a general indicator, but there are some exceptions when an image may contain repetitive patterns with edges that may generate more feature points, but result in less effective tracking. Vuforia sees targets in grayscale not color, so some colors when converted to grayscale may have higher contrast edges which may yield more feature points. Feature points contained in printed text within a target can also be hard to track. See the section "Avoid repetitive patterns" in this guide:

https://developer.vuforia.com/library/articles/Solution/Natural-Features-and-Ratings

 

5 stars images not correct

September 17, 2015 - 7:32pm #4

The star rating is a general indicator, but there are some exceptions when an image may contain repetitive patterns with edges that may generate more feature points, but result in less effective tracking. Vuforia sees targets in grayscale not color, so some colors when converted to grayscale may have higher contrast edges which may yield more feature points. Feature points contained in printed text within a target can also be hard to track. See the section "Avoid repetitive patterns" in this guide:

https://developer.vuforia.com/library/articles/Solution/Natural-Features-and-Ratings

 

5 stars images not correct

September 17, 2015 - 12:24am #3

dm3d wrote:

In many of your targets, you are using Frame Markers which are different than Image Targets. Frame Markers don't need to be uploaded to the Target Manager. Frame Markers can be recognized based of the border pattern of dots. Image Targets need feature rich details in order to be tracked and must be uploaded to Target Manager. Here's some articles to explain further details:

https://developer.vuforia.com/library/articles/Training/Frame-Markers-Guide

https://developer.vuforia.com/library/articles/Training/Image-Target-Guide

Sorry but we disagree.

We put a frame marker inside an image which gave us a 5 stars (Alitalia (targets 14)->markereng and marker) to switch quickly during test to undestand the problems we faced the whole august (check the dates).

 

markereng and marker were 5 stars and we used as image targets, grayscale images displayed that the image has a nice number of tracking points.

 

In other tests (alitalia3) we changed the center of the marker from green to light gray and it worked flawlessly (at least like a 3-4 stars.

 

Seems green color when printed creates huge problem in tracking depending on printer.

Gray version and green versione attached (from Alitalia (not working, green version) and alitalia3 (working, light gray version)). 

5 stars images not correct

September 16, 2015 - 3:20pm #2

In many of your targets, you are using Frame Markers which are different than Image Targets. Frame Markers don't need to be uploaded to the Target Manager. Frame Markers can be recognized based of the border pattern of dots. Image Targets need feature rich details in order to be tracked and must be uploaded to Target Manager. Here's some articles to explain further details:

https://developer.vuforia.com/library/articles/Training/Frame-Markers-Guide

https://developer.vuforia.com/library/articles/Training/Image-Target-Guide

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