Need help on sketch recognition algorithm

I want to develop a sketch recogntion system. The input for the system will be taken from touch based devices (iOS, android) and the recogniton algorithm should detect the basic shapes like circle, rectangle, bezier curves etc. I want to make something similar to: http://www.youtube.com/watch?v=xvPLRRt79uo

I am new to machine learning. I dont know where to start from. Are any standrard algorithm exists for sketch recognition?