How do you merge two videos recordings by separate cameras of the same view. here is detailed question?

ello, I need a tool that could merge recordings of the same view by two separate cameras located at different angles and eliminate the object that appears to both cameras. Imagine I want to record the classroom, whats on the blackboard to be more precise, but there is always a teacher walking between the cameras and the blackboard. If I locate two cameras in two different corners of the room under different angles from the blackboard so that each of them sees a the blackboard and the teacher but each of them will have different blind spots on the blackboard. when I combine the two views merging them on common region (part which both cameras can see) I will be able to get the view of entire blackboard. please refer to this pic to understand what I mean *ttp://i56.tinypic.com/2reo08i.png Is there any tool that can automatically do that? thanks a lot I really need this for my term project at the university