Indexing and teaching focus mining of lecture videos

This paper proposes an indexing and teaching focus mining system for lecture videos recorded in an unconstraint environment. The slide structure can be reconstructed by an edge-based shot change detection algorithm. Besides, the teaching focus can be extracted according to instructor's behavior, including the gesture, the lecture time for each slide, and the speech speed. Experiment results show the feasibility of the proposed method, that is, the slide shots can be correctly detected even if the illumination conditions is variant or the slides are obstructed by the instructor or students, and the teaching focus can be well extracted to provide learners an efficient way to study.