roboforum.ru

A simple framework for creating real-time augmented reality applications
A multiplatform library (Windows, Linux, Mac OS X, SGI)
Overlays 3D virtual objects on real markers ( based on computer vision algorithm)
A multi platform video library with: 
multiple input sources (USB, Firewire, capture card) supported
multiple format (RGB/YUV420P, YUV) supported
multiple camera tracking supported
GUI initalizing interface
A fast and cheap 6D marker tracking (real-time planar detection)
An extensible markers patterns approach (number of markers fct of efficency)
An easy calibration routine
A simple graphic library (based on GLUT)
A fast rendering based on OpenGL
A 3D VRML support
A simple and modular API (in C)
Other language supported (JAVA, Matlab)
A complete set of samples and utilities
A good solution for tangible interaction metaphor
OpenSource with GPL license for non-commercial usage

MPORTANT NOTICE REGARDING YOUR RIGHT TO USE ARTOOLKIT:

ARToolKit is made available freely for non-commercial use under the GNU General Public License. Commercial licenses to a professional implementation of ARToolKit are available for users for whom the GPL is not suitable, or who require a higher level of support, or who require customization or other specialist modifictions. Commercial licenses are administered by ARToolworks, Inc., Seattle, WA, USA. 
http://www.hitl.washington.edu/artoolkit/license.html

IplImage *bgra;
...
bgra = cvCreateImageHeader(cvSize(xsize, ysize), IPL_DEPTH_8U,  4);
...
dataPtr = (ARUint8 *)arVideoGetImage()  // получение изображения
bgra->imageData = (char *) dataPtr;
cvFlip(bgra);