OpenCV provides several Haar Cascade classidiers for face detection:
- haarcascade_frontalface_alt.xml
- haarcascade_frontalface_alt2.xml
- haarcascade_frontalface_alt_tree.xml
- haarcascade_frontalface_default.xml
I wonder what is the difference between these classifiers.
I have noticed that, in application, the "default" version returns more false positives than the "alt" and "alt2" versions; and the "alt_tree" version is the most rigorous one. However, I am looking for their fundamental differences. For example, if anyone knows what database is used for their training.
Thanks