Design And Implementation Of Super Large-screen Interactive Electronic Whiteboard Based On Optical Image Positioning

With unceasing advancement of modernization and informationization, the interactive electronic whiteboard is widely applied in the teaching, training, the conference, as well as in the demonstration. However, there are many disadvantages in the existing electronic whiteboard, such as high cost, poor protability and anti-interference performance, so it cannot satisfy the military and classroom needs.For the actual demand of military and college, one design proposal of super large-screen interactive electronic whiteboard based on optical image positioning is proposed. The program (?) embedded technology and image processing techniques to locate, and combines with PC software to realize the function of mouse operation and handwriting. The whole system has the characteristic of good protability, low cost, large-screen display and certain anti-interference (?).The main works of this thesis are as following:1. After learning the design principle of embedded systems, the program of interactive (?)onic whiteboard with large screen display and low cost is proposed, and hardware design principle and software implementation method of all modules are elaborated;2. After studying the method of designing GUI programs with Qt/Embedded technology in embedded Linux platform, the application procedure and GUI of system are completed;3. The new method of electronic whiteboard system calibration is proposed based on CCD (?), and it extracts successfully image pixels of reference points for adopting Harris’Corner detection algorithm. According to the basic property of projective geometry, the relations between image pixel points and actual points is derived, then the optical centers of CCD cameras are obtained;4. After analyzing of different interactive pen (ordinary pen, finger or pointer) of imaging features, the method of threshold segmentation based on gray level transformation is designed, and the search scope of gray level is reduced to speed up the data processing speed;5. In the VC++ 6.0 development environment, PC software based on MFC is designed for realizing the mouse operation and handwriting function;6. The thesis tests on system performance for the interactive electronic whiteboard, the results indicate that the system can basically meet the requirements. The effect of increasing electronic whiteboard size to system performances is discussed, then it is confirmed that the electronic whiteboard system of this thesis can definitely achieve large-screen display function in the case of no additional cost.