Design And Research On Key Technology Of Copyboard

Traditional whiteboards are widely used in conference and teaching. But with the rapid pace of society, conference discussion and teaching notes are required to be digitized,in order to realize the functions of information sharing and recording. And now, the technology of scanning and embedded device have been widely used in people's daily life, and if transforming the traditional whiteboard with these technology, then we will not only preserve the advantages of the traditional whiteboard, but also reduce the difficulty of designing a new product, which is able to scan the contents of writing on the whiteboard, save the image and print it out by a printer.Copyboard, as the substitute product of the traditional whiteboard, provides the function of scanning the contents of writing, auto saving the scanned image file to USB flash disk, and monochrome/color printing. The main hardware modules that copyboard contains includes: X210V3 development board, CCD image sensor, GL847 scanning controller, WM8196 ADC(Analog-to-Digital Converter) and stepping motor etc. The linear CCD image sensor can scan the contents of writing on the whiteboard to get the primary analog signal of the scanned image. WM8196 ADC is used for converting the primary analog signal to digital data and output it. GL847 scanning controller's function is to calibrate and correct the image, in order to enhance the quality of the image. After being processed by line shift module, the image data will be saved as an image file in JPEG format via the interfaces supplied by the jpeglib library. And users are allowed to press the buttons to select the corresponding function, for example, saving the image file to USB flash disk or print out the image.This paper introduces the electronic whiteboard realized in different kind of approaches, conducts a thorough investigation on the technology of scanning, system transplantation, image data compression and printing, and proposes integrated solutions. In accordance with GL847 scanning controller's characteristics, a method to calibrate the image which is based on black-white shading is proposed to improve the quality of the image, and an improvement on the acceleration curve is made to stable the accelerating process of stepping motors. According to the special structure of the scanning array in TCD2252D image sensor, a reasonable scheme of line shift function is put forward to settle the line shift problem. After being reconfigured, the Linux kernel is transplanted to the embedded platform to provide the supports on USBFS and USB printing service.Copyboard is reasonably designed. It has high performance-price ratio and notably improved efficiency of education and conference recording. Through the research and design of the key technology of copyboard, the understanding of the whole system and system modules is deepened, and the experience and technology are helpful to the subsequent development of the system.