A well-presented chalk talk often provides a rich and interactive learning environment that cannot easily be replaced with PowerPoint slideshows. However, it has a disadvantage in that information written on the blackboard is hard to archive or share with others who do not attend.

We developed a ChalkTalk system that automatically produces e-learning materials from a videotaped chalk talk lecture in front of an ordinary blackboard or whiteboard. The system separately captures images of the blackboard with and without the lecturer from a chalk talk lecture video recorded with a high-definiton digital camcorder placed in the back of the room. The ChalkTalk system automatically tracks the lecturer as he/she moves in front of the blackboard and stores the images near the lecturer as a movie. Meanwhile, it stores occasionally updated information on the entire blackboard as an animation of snapshot images. Our method can dramatically reduce the necessary network bandwidth.