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Features found are only in upper portion of trackable

August 1, 2013 - 1:23pm #1

I tried improving my trackable by using the "local contrast enhancement" technique from this link: https://developer.vuforia.com/resources/dev-guide/image-target-enhancement-tricks. I was able to get a 5 star trackable image, but when I go to look at the features Vuforia found, I see the 8% border around my image, but then I see a maybe 25-35% portion at the bottom that has no features. Is there a limit to the amount of features looked for and if that maximum is hit the rest of the image is ignored? Is this going to cause any issues because the features aren't evenly distributed in the image?

Features found are only in upper portion of trackable

February 17, 2014 - 3:07am #12

UPDATE:

the issue is fixed on the current Target Manager.

Features found are only in upper portion of trackable

September 10, 2013 - 4:42am #11

Hi eskimos, we have identified the issue related to your image, and we are working on a solution.

We will update you on the progress of this.

Features found are only in upper portion of trackable

September 7, 2013 - 3:52am #10

yes here

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Features found are only in upper portion of trackable

September 6, 2013 - 9:58am #9

Yes , we're looking into the problem - it's doesn't affect the Trackable itself, only the hashed image, and only certain target images are affected.

Can you send me an example of the target that you're seeing this on?

Features found are only in upper portion of trackable

September 6, 2013 - 9:22am #8

im getting the same thing features in the top 75% of image, nothing in bottom 25%. I rotated the image 180 and the same thing -features in the top 75% of image, nothing in bottom 25%. Im guessing bug in the display features part of the website.

Features found are only in upper portion of trackable

September 3, 2013 - 8:27am #7

This is the most simple experiment i can find at the moment. The Top has lots of features marked but the bottom nothing.

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Features found are only in upper portion of trackable

September 3, 2013 - 8:21am #6

I think that it's a bug. Can you send me an example of the target you're using?

Features found are only in upper portion of trackable

September 3, 2013 - 8:12am #5

On most of my targets the Target Manager isnt showing features in the bottom as well? is this just a display bug of the "show features function"

?

Features found are only in upper portion of trackable

August 5, 2013 - 8:03am #4

Good. I've checked your targets and confirmed that the LCE version is missing feature hash marks in the region you described. But I suspect that this is an issue w/ the representation on the target manager page, as your testing confirms that the features are actually recognized by the tracker. Thanks for the follow-up.

Features found are only in upper portion of trackable

August 5, 2013 - 7:51am #3

Yes the lower region does. This image I used was one that I applied local contrast enhancement to, as per the tutorial. I attached it and the original so you can have a look if you want.

 

I occluded all four "halves" of the printed image, and tracking seems to work as expected. I guess that means it seems to work empirically.

 

Features found are only in upper portion of trackable

August 1, 2013 - 2:49pm #2

The feature count is not limited.

Does the lower region of the image contain features that should have been acknowledged?

My advice is to test the target, and specifically occlude the upper region of the image to determine whether the lower region is useful for tracking. You should test the other low rated targets that you have as well. They may perform adequately.

The Target Manager rating is a simplified composite rating of mulitple factors. Low rated targets may perform better than you might expect from their ratings. This is especially true for the current SDK because we've introduced improvements that make tracking quite robust. So it is worthwhile to evaluate your targets empirically.

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