Thursday, January 24, 2008

WebCam + OpenGL + OpenCV head tracking = Immersive 3d environment

UPDATE! This sample has evolved to a project sponsored by Google. Please check

This is my first attempt to create a 3d immersive environment using a simple webcam to track head's position.

This video shows my approach to combine OpenCV head tracking with a 3d OpenGL environment so that the user will see objects from their head's point of view. Since head tracking is 2d, no depth information is obtained. Besides that, it takes the face recognition algorithm around 200ms, which yields low fps (about 5). I'm currently trying to improve that :)

Well, thanks to Walter Piechulla I could decrease detection time to around 20ms using the flag CV_HAAR_FIND_BIGGEST_OBJECT - which makes opencv detect only one face - in a parameter to the function cvHaarDetectObjects, that looks like this now:

cvHaarDetectObjects( small_img, cascade, storage, 1.1, 2, CV_HAAR_FIND_BIGGEST_OBJECT,
cvSize(30, 30) );

(by the way, I had to update OpenCV from CVS)
As soon as I get some time, I can make another video showing speedup :D
Thanks Piechulla

The new version is available here:

Tuesday, January 15, 2008

Avoiding ACM Web Account to download papers

In case you are a researcher and you really want that paper but ACM web account is blocking you from seeing it, you might try the following:
  • Access the paper from your university - some universities have granted access because of their IP, which makes it very easy for researchers to download the papers
  • Get yourself an ACM Web Account
  • In case you are a researcher and you simply are not at the university when trying to see the paper, an useful workaround can be looking for the author's homepage or the congress that published the article
For instance, I was looking for the article "Early Experience with Scientific Programs on the Cray MTA-2" which leads me to this page, which doesn't allow me to get the file. Then, googling for the first author and a related word "Wendell Anderson cray mta 2" leads me to the Congress page, from where I can get it. It generally works :)
Besides that, ACM Web Account seems to be a great service. I would really recommend getting one account :)
Hope this post can help you!

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