Indoor Location Tracker for Automated Cameraman
Doing a project like this from scratch is very complex, involving a knowledge of signal processing algorithms etc. However, there is a solution that might be within your experience level. Look at a project called PIXY. It's a smart camera designed exactly for what you want. It can track color tags placed on the object to track. It even has it's own scripting language etc, etc, and a good support forum. It's fairly cheap too, at about $70. There might even be a raspberry pi interface for it already.
Good luck...

P.S. Here is the project, and there is indeed a link for raspberry pi.
http://cmucam.org/projects/cmucam5/wiki