The Design And Implementation Of Electromagnetic Whiteboard

With the continuous development of science and technology, the traditional teaching method of combination of chalk, blackboard and eraser have been gradually improved, the multimedia classroom with rich multimedia resources creates convenient conditions for teaching and improves learning efficiency. At present, the use of multimedia teaching in colleges and universities, often relies on the combination of projector, computer and curtain, while in primary and secondary schools; There is an entirely different scene:interactive multimedia teaching methods based on whiteboard. In recent years, the situation of the use of the whiteboard is better and better, because interactive whiteboard bring us into a work environment of higher efficiency and easier way of learning. In the electronic whiteboard system, whiteboard connects with computer, they can complete the real-time communication, so that the user can switch anyone freely between them. For example, when the user saves notes in which something have been modified, the user can complete this operation on the whiteboard directly instead of going back to the computer.In the company where I have a internship, one of the product is whiteboard. Against this background, the paper has introduced one of the interactive whiteboard-electromagnetic whiteboard, and also the analysis of its design and implementation process are described clearly, at the same time, the paper has discussed a number of key issues about electronic whiteboard in the field of multimedia applications. The paper has taken full use of the equipments used in the in R&D and production in the company, and has tested data and methods repeatedly. After that, certain points about improvement measures of electronic whiteboard in electronic whiteboard system have been proposed. In order to dislay the same content in real time between the large whiteboard screen and computer screen, we must solve the problem of coordinate transformation. The paper proposed a new method-perspective projection transformation, which based on the detail analysis of variety of coordinate conversion methods in the market. Perspective projection transformation algorithm has eight unknown number which make coordinate conversion accuracy improved significantly compared to the other coordinate transformation methods (have less than six unknown number).On the other hand, a special electronic pen is necessary for the electromagnetic whiteboard in the process, which involves the positioning accuracy problems about the operation of the electronic pen on the whiteboard screen. According to the provisions of the state, the distance between the center position of display point and place where pen write is a standard which reflects the positioning accuracy of a whiteboard. Different manufacturers use different positioning methods on the market, but most of them use the simple linear algorithm which is combined with micro-controller to complete the positioning of coordinates. In the paper, we made smaller changes about this localization algorithm and proposed an another positioning methods:bilinear interpolation algorithm. The positioning accuracy raises0.13mm after measurement repeatedly.The paper introduces the electromagnetic whiteboard systems from the hardware to software, including the design principles and methods of hardware board, registers configuration in program design, drive module of the host computer, the establishment of data acquisition modules and communication modules, and also gives a brief description on the interface module of application program. At last, the article makes a test for several key performance indicators of the system, the result shows that the system makes a good performance.