Javascript motion tracking

soundstep.com

43 points·middleman90··6 comments

If I understand this correctly, this is not motion tracking in Javascript, rather the JavaScript just renders the picture on the video using precalculated data about the position of the corners...

That seems to be the case given that http://www.soundstep.com/blog/experiments/jstracking/js/app.... starts with var tracking_data = [[243.625,172.75,249.014,171.041,252.918,169.895...

would "motion drawing" be a better title? How would you condense your description into something the average person could understand? That may help the creator.

Maybe "Overlaying picture over video in pure JS + <canvas>"?

Unfortunately, I believe that this article was mainly popular because of it's catchy, yet wrong title (which would certainly be revolutionary if it were correct).

That doesn't mean, of course, that what the article describes is trivial/easy. I've studied math, but I'd still have to think for quite some time to figure out what kind of matrix transformation to perform... and, making it 100+ fps in Javascript is impressive in itself!

After skimming js/app.js, this does seem to be the case.

Back in 2009 I did some work on augmented reality in the browser[1]. Back then there was no WebRTC, so I had to shim Flash to Canvas to get webcam images, and I implemented image tracking using a simple color tracking algorithm.

If this really is doing image tracking in JS (as tomp noted the explanation isn't clear) then I'm very impressed.

The previous state of the art was some great face-detection code I'd seen, but it is much slower than this.

[1] http://nicklothian.com/blog/2009/11/18/augmented-reality-vir...

[2] http://liuliu.me/eyes/javascript-face-detection-explained/, http://apprtc.appspot.com/html/face.html

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