Hi. I've seen over there that the Haar object detection procedure implemented in OpenCV has a patent. However, I've also seen a couple of pages that explain that depending on how the models are built we can use OpenCV for object detection patent-free (but they aren't sure 100% of this):
http://rafaelmizrahi.blogspot.com.es/2007/02/intel-opencv-face-detection-license.html
http://sarnami.net/face-recognition/news/opencv-face-detection-and-patents-or-how-to-train-your-classifier-without-patent-infringement/
There are some pre-trained Haar-based models in OpenCV that mention they are "tree-based" instead of "stump-based" as explained in the pages above so that they can be patent-free. So... do you think it would be possible to use these detectors as patent-free? (it's quite confusing for me all this patent issue, I'm not a lawyer). Thanks!