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marker source image size question

February 24, 2012 - 8:09am #1

I have a very big marker ( 2m by 1m). I read in some faq that it is wise to use an image that is close to the one that is put into vuforia - basicly the camera image size. thing is, i have a scene like a window into something ( and also extending into userspace from the marker). this means that the user will look at the marker from all angles and especially distances. i tried an image thats 1000px and one thats 2000px but i got the same tracking quality and the yellow crosses seem identical. since i can walk close to the marker I thought that a higher res image would provide a better tracking because of its resolution (when closer). Is there a difference ?

Simon

Re: marker source image size question

February 27, 2012 - 6:29pm #5

Yes, tag it on as a post to this thread:

http://ar.qualcomm.at/node/2000011

We'd love to see it!

- Kim

Re: marker source image size question

February 27, 2012 - 1:22am #4

Thanks a lot. This is really a helpful place. You guys seem to care. Thank you.

I have to deploy the project basicly tomorrow and i don't think i want to change the setup (multimarker) in a day because the client seems happy with the tracking. i still have very good tracking on the 2m marker when as close as 30 cm. Good job.!

Do you have a forum to show current stuff done with vuforia?

Simon

Re: marker source image size question

February 24, 2012 - 9:43am #3

Also increasing the resolution of an image isn't going to have any effect if the increase does not reveal additional details in the image that will be captured as features. This is probably the case w/ your comparison. For example if I were to provide the TMS with two images of an X, one at 1000px and another at 2000, the features extracted from these images would still be the same because the additional resolution is not providing additional details in the image.

But if I were to do the same with this image, the increased resolution would likely provide additional detail and a more robust target.

Re: marker source image size question

February 24, 2012 - 9:05am #2

There is a limit to the number of features that can be handled per target, so at some point higher resolution doesn't buy you much.

You may want to consider breaking your large target into several subtargets and stitching them together to form a multi target. If the user will spend most of his time viewing only a portion of the target (rather than the entire thing) this might let you take more features into account. I recommend using the new 1.5 release if you decide to try this, it has several improvements to multi target tracking.

- Kim

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