Fields I have not covered-geometric sketch recognition

Today I accept a new task. The head of the department asked me to develop a geometric sketch recognition system. The approximate function is to sketch hand-drawn geometric images (such as straight lines, rectangles, circles, and so on) recognizes as a standard vector ry. Today, all my basic knowledge of Handwriting Recognition adds up to the following process:

How should we perform each step of this process. I hope your colleagues will give you a lot of advice and have good experience or good introduction. Please give more guidance or be interested in technical cooperation )!