Design And Implementation Of Video-based Positioning Whiteboard System

With the development of technology, the single teaching method in the past has been improved step by step. With the multi-channel presentation of teaching contents, multi-media classrooms combine the theoretical and intuitive teaching and mobilize the students' interest in learning. At present, the common solution mainly contains projector and computer in the applications of the multi-media classroom. Such a solution can easily presente computer courseware, video, audio and other educational contents in front of students, however, in the vast majority of teaching practice, the projection screen in the multi-media classroom is only used as a display screen, teachers must return to the computer to mark or take other operations to the contents of the projection, thus reducing the efficiency of the teaching.In this paper, in the background of the whiteboard used in the teaching, we carry out specific research work on a number of key issues existing in the teaching application which uses computer supported multimedia large screen projection. In this paper, with full use of existing equipment in multi-media classroom, we form whiteboard system architecture by adding a camera and building system software. With monocular vision theory applied to the whiteboard area, the projection display screen is converted into a whiteboard screen which can feed back information. By using this improvement, it can take processing or labeling operations on the contents projected to the screen, realizing two-way interaction communication between the whiteboard and the computer.The whiteboard system based on monocular vision studied in this paper, different from the other whiteboard system based on machine vision, uses only one camera to carry out locationing. It presents three different locationing algorithm in this paper: First, it is the coordinate transformation algorithm which is deduced from the locationing model; Secondly, it is the algorithm that using texture mapping algorithms in computer graphics to calculate the coordinates of the light point in the projection screen, which is not only simple but also reduces the complexity; Finally, vector additive location algorithm is proposed based on the analysis of mouse usage. i.e., the position of the pointer on the screen and the position of the light point on the projection screen may not coincide, however motion vector of the pointer on the screen can be got by calculating motion vector of the light point on the projection screen.The last part of this paper analysis the monocular vision-based whiteboard system architecture and software workflow, summarizes the characteristics of electronic whiteboard based on monocular vision, points out its shortages and problems to be solved, also it makes an expectation on electronic whiteboard.