Hybrid Audio-video Recording System for PBL Lecture in Round Sitting Classroom

The PBL classroom is a circular area in which students study in a circle. At the same time, teachers should have a complete understanding of the participation of each student in the PBL classroom. Due to the shortage of manpower resources, a system is needed to record students' behaviors. The typical solution is to deploy a lot of prep work, either voila recognition camera installation or immobilization, which is not easy to deploy in PBL classroom. In this paper, we propose a kind of lightweight equipment, which locates in the center of the round table and is scalable to similar classroom. It can support speaker localization function, by hybrid audio-video localization algorithm. In this scheme, the basic positioning is through sound field positioning and six-microphone array, and in some difficult situations, such as people sitting close, people moving, will make the video decision method. The video is shot by a fish-eye camera for face/mouth detection and can also calculate positioning angles. Finally, the test results show that this method can effectively identify the speaker's position in class and record it.