I am doing a project on hand sign recognition on a static image. Can I use just Haar training to accomplish this?
As what I've understood, it is somewhat similar to the concept of neural networks.
Using Haar training maybe help to detect the hand, but not for recognize.
The people use many approaches, so I cannot give a unique. You could make some research using Google Scholar and use the keywords "hand sign", "recognition" and "detection". Some tips: you need to segment the hand and use some template matching or other method to recognize the format. There is also a project for hand gestures here.