| Is introduced in this paper based on FPGA and contact image sensor(CIS) to achieve the double scanning system.Through the two CIS scanning way to implement the image real-time scanning on both sides of the one paper, at the same time also realized the image data real-time processing and drive other peripheral chips in the FPGA chip internal, and complete the change of algorithm and parameter and upgrades the system function at the PCB. The main contents of this thesis were building the hardware platform of PCB board for image acquisition and analogue-to-digital conversion processing system and write the code of drive and data processing module with verilog, as well as the simulation of verilog code in modelsim and the PCB,and the actual scanning circuit system debugging. The designment of each modules included the peripheral PCB circuit of CIS, the time driver of CIS in FPGA,the peripheral PCB circuit of analogue-to-digital chip WM8214,the time driver and the parameter configuration of analogue-to-digital chip,the peripheral PCB circuit of exposure of chip TLC5917,the time driver of TLC5917 in FPGA,the module of clock control Phase Locking Loop(PLL) in FPGA,the module which used ping-pang operation to process the image data in FPGA. The working process of this system is configuring of time driver of CIS and the exposure chip to collect the image data with three data channels and transfer the analogue data to the analogue-to-digital chip in the parallel manner.Then conversing the parallel data into serial data in 8 bits accuracy,and transferring to the chip of FPGA. After transferring, the chip of FPGA use the internal FIFO to buffered,broke off both ends and sorts these datas.The system would store the data which would be transferred to the chip of USB in the peripheral chip of SDRAM.At last,the data from USB chip would be coded and packaged, then the data could be transferred to the PC and corrected. After a series of processing, the image can be rendered in computer. |
