For those developing on Debian based Linux, these are the steps:<p>1. Install python-opencv package with apt-get/aptitude<p>2. You can get the Haar cascades here - <a href="http://alereimondo.no-ip.org/OpenCV/34" rel="nofollow">http://alereimondo.no-ip.org/OpenCV/34</a><p>3. Run the same code, just make sure to use one of the cascades downloaded from step 2<p>Line 60:
parser.add_option("-c", "--cascade", action="store", dest="cascade", type="str", help="Haar cascade file, default %default", default = "/usr/local/Cellar/opencv/2.2/share/opencv/haarcascades/haarcascade_frontalface_default.xml")
Change default to the haar cascade file path, or use --cascade option to specify it.<p>4. Execute<p><i></i>Edit: For non-Deb based distros<i></i>, use your package manager to download/install opencv for python (or compile it) and continue from step 2.
FYI, there are OpenCV-based face detection nodes in ROS (Robot Operating System by Willow Garage) that publish the detected face positions using a stereo pair (which prunes false positives based on face depth/size estimates). Slightly modified to use one camera or a Kinect, and you would have a python consumer node that requires a mere 5 lines of Python code. ;-)<p><a href="http://www.ros.org/wiki/face_detector" rel="nofollow">http://www.ros.org/wiki/face_detector</a>