Archive for October, 2010

Pure AS3 version of Lucas-Kanade Optical Flow

Time for some playing.

As we tried to figure out how to get an accurate tracking using a webcam we stumbled upon different methods.

The first approach was using Haar Cascades. Trying to optimize them ended up in x-thousand lines of unrolled code in one function. I wrote an AIR app which transformed cascade xmls to a function AS3 class. Execution time was really good. If I remember right it was about 6ms for finding 2 eyes. But it was not accurate, found the eyes randomly. So we decided to skip Haar Cascades and tried to find another method which was more accurate.

We found OpenCV and the included lkdemo was what we thought would fit our needs. We did a complete rewrite in AS3 and optimized the hell out of it.

Optical Flow Demo (SWF) (webcam required)

On my machine it needs about 1ms per point + 2ms function overhead.

For optimisation we used Joas Apparat ( .

Categories: algorithmn, as3, flash

So I opened up a blog

So I opened up a blog.

My intention is to write some articles about my daily work. What am I doing how, and why? It may be interesting for some people. But first of, who is Marcel Klammer:

I’m a Flash/Actionscript developer from Leipzig, Germany, freelancer since September 2007, 27 years old. My daily work is about agency work for big national and internatiol operating companies, mostly advertising campaigns using Flash/AS3.

If you are interested in hiring me, don’t hesitate to contact me. Find me on

Skype: Marcel Klammer (marcy_lh)

Thanks for reading,


Categories: Uncategorized