1 | initial version |
The only patented algorithms in openCV that cannot be used for commercial use are SIFT and SURF. Even then if it is for research or projects in an academic context, you can always apply for a free license with the owners of the patent.
Haar wavelet object detector, the technique of Viola & Jones is free to use as a face detection module, even in commercial applications, as is the face recognition algorithm based on fisher or eigenfaces.