Optimizing Of Data-acquisition System For Laser Electronic Whiteboard And Realization Of USB Interface

The electronic whiteboard, a piece of equipment supporting the interaction between people and computer in education and conference, has surveyed the electronic technology, software technology, internet technology and other high-tech means and is now widely used in many fields, such as multi-media teaching, on-line distance education, internet conference etc. With the development of relevant technology, the electronic whiteboard has evolved into an interactive system, which has greatly facilitated human communication in speeches, lectures or presentations in conferences.The dissertation of laser electronic whiteboard is sponsored by the development fund of Commerce export product and the project No. 2006103. Laser electronic whiteboard, which has strong anti-jamming, large writing area and light and passive pen, has good market prospect and social value according to laser localization technology.The main tasks and contributions of this paper are as follows:Firstly, this paper has fully researched the basic theory of laser whiteboard, and analyzed the existing problems in system, improved the system hardware circuit of signal processing, upgraded the transmission interface for USB interface, and expanded the SD card interface which makes the laser whiteboard complete the real-time storage of writing information in the absence of computer co-ordination work. At the same time, because of the use of C5509A, the improved system has not expanded SRAM, PIC microcontroller, the converter circuit for serial interface and so on, so that it has reduced the complexity of system, improved the stability of system, enhanced the portability of system and facilitated the succession work of system.Secondly, this paper has developed the firmware program and the application program of USB module in laser whiteboard. Practice has proved that the program developed in this paper could complete the data communication between the laser electronic whiteboard and PC, communication stability, and the low risk of errors.Thirdly, optimize the receiver circuit of laser electronic whiteboard. Access to a lot of information, the self-excitation oscillation phenomena of laser receiver circuit has been eliminated. At the same time, the circuit has been made to a simple amplifier of two steps according to the reference design of datasheet. By testing and comparing, the receiver circuit debugged has met the requirement, the jitter problem of motor has been solved, and the laser whiteboard could complete the basic writing function now.Fourthly, research the color recognition algorithm and penupdown algorithm of laser whiteboard. In this paper, the research process of color recognition algorithm has been given, and correlation method is summed up to solve the color recognition at the end. At the same time, the research to penupdown algorithm has carried out, which has laid a foundation for the software implementation of the algorithm.The main contents of this paper are as follows:In chapter one, common localization technology of whiteboard has been summarized, the research background and significance of laser whiteboard issue has been arised and the main content of this paper has been pointed out.In chapter two, the basic component of laser whiteboard system have been introduced. The localization technology of laser whiteboard has been focused on.In chapter three, optimization design to the signal processing system of laser whiteboard has been introduced. The main design includes the power circuit of system, A/D circuit, CPLD interface circuit, DSP interface circuit, real-time storage circuit and USB interface circuit and so on.In chapter four, the driver program have been developed for USB interface of laser whiteboard. The principles and procedures of firmware development have been given detailedly. Use the application program to debug it, and the debugged result is summarized.In chapter five, on a basis of requirement to receiver signal of laser whiteboard, this paper has designed and debugged the receiver circuit.In chapter six, the key algorithm of laser whiteboard have been researched depthly, and reasonable solution schemes have been proposed. The key algorithm include color recognition algorithm and penupdown algorithm of laser whiteboard pen.In chapter seven, a summary of the dissertation is given.Be restricted by time and the author ability of this paper, there are the following problems that needed be settled as soon as possible:1. Color recognition algorithm and penupdown algorithm also should be verified and improved in practice.2. The design and development for SD card program is important to the expansion of laser whiteboard in the application field, so that initiating the development of SD card is imperative.3. The laser whiteboard can not correctly display the pen style and rhyme of the actual writing.4. Test the system of laser whiteboard, so that the problem can be found and detected. Solve problems timely, which will lay a solid foundation for marketing.