Meet qtrack

It stands for “quadrilateral tracker”, little pet project I have been sporadically working on since october. I should have given it more love, but I didn’t want this post to drag into next year, so here goes “version 0.9”:

After December 7th, qtrack is the only free, as in “free beer”, flash 3D AR tracker. Curious why? There are many reasons for that. For one, most of its code is already available for free elsewhere on the web. But another, more important reason is that I just don’t see enough flash AR around, and setting this thing free is my modest contribution to spark some more creativity in the field :) I mean, when was the last time you actually saw flash AR game, huh?..

Any way, back to qtrack – it works similarly to famous FLARToolKit, except it is not that advanced and currently implements only single instance of single quad marker tracking. On the bright side, it is less restrictive regarding marker shape – all these markers could be tracked with qtrack, for example:

So, this is something you can try today. Zip file comes with two simple examples for Away Lite and Alternativa engines, and soon short video tutorial will follow. In January I will try to further improve qtrack in the areas where it currently have problems, and release stable version 1.0.


As I said, most of this thing is based on free code snippets published or inspired by various people. This includes blob detection (Tomek), homography (Zeh), marching squares (Sakri), Otsu thresholding (Andrew), automatic thresholding (some unknown guy), brilliant camera activity trick (Deepanjan). Even my complex numbers experiment found its way into this – I used it for pose estimation. So big thanks goes to all these people who have posted right things at right time for me to come across – without you qtrack would never happen!

11 Responses to “Meet qtrack”

  1. 1 Ryan Hill December 31, 2010 at 00:45

    Hey Makc,

    Looks interesting. We’ll have to try it out and make something fun.

  2. 2 dsirijus January 1, 2011 at 14:50

    Nice, will give it a go.

  3. 3 nicoptere January 3, 2011 at 15:01

    lightweight, fast, accurate and… free
    thanks a lot! :)
    stupid question now: how can we encode a marker?

  4. 5 dsirijus January 4, 2011 at 14:53

    My comments/questions on the lib so far:
    – Seems that it performs better in the middle of webcam than around the edges. Is that to be expected, since cams distort most there?
    – Why is there no marker size specification?
    – (related to the previous note) Why is the default to have transformation matrix in space of 4×3 (or whatever on other cams) than in webcam object? Wouldn’t that be more sensible?
    – This is my particular use case issue, but… I’m not running AR on my own stream. I’m running it on video stream of some other broadcaster or filtering webcam data somehow, and I cannot accomplish that through qtrack (correct me if wrong). Now, even beyond AR there are use cases like tracking on generated graphics. I wouldn’t know how to do any of those through qtrack.

    Anyways, very decent work that “should have been given more love”. A LOT clearer than FLARToolkit.

    • 6 makc3d January 4, 2011 at 15:26

      @dsirijus, quick answers:
      – that’s to be expected, if your specified focal length doesn’t match actual camera focal length. I will make an utility to measure focal length later.
      – marker size is 2×2. if you need scaling, use two nested 3D objects (or prepend scale).
      – I don’t understand this question, sorry :)
      – yes, QuadTracker class was made to work with a webcam. underlying QuadDetector can work with anything, so in theory you could have YourCustomTracker that works with something else.

  5. 7 Lion May 17, 2011 at 13:06

    ur download link doesnt works. did u removed it. would like to try it.

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Old stuff

December 2010

Oh, btw…

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