How were the stock face detectors trained/tested?
The OpenCV distribution contains several xml files describing classifier cascades for frontal face detection. Can anyone tell us what database(s) and methodology were used to train and test them? Specifically, I am thinking about haarcascade_frontalface_alt.xml, haarcascade_frontalface_alt2.xml, haarcascade_frontalface_default.xml, and lbpcascade_frontalface.xml.
Is it a secret?
Somebody must know the answer. Don't they need to get retrained whenever related code changes?
I don't know the original process but the links given below might give you some idea.
http://docs.opencv.org/doc/user_guide/ug_traincascade.html
http://coding-robin.de/2013/07/22/train-your-own-opencv-haar-classifier.html
I am not asking how I could do training; I am asking for details on how the particular models in the OpenCV distribution were trained. It seems strange to me that an open-source project would keep these details secret.