Development Of Micro-nano CT Data Transmission System Based On GigE Vision Protocol

With the development of science and technology and industrial level has increased,in CT detection demand direction,especially the material microstructure,biological tissue microstructure examination imaging applications,for high resolution fast 3-d imaging Xray CT imaging proposed the urgent demand,high resolution CT imaging technology become a research hotspot.Micro-nano CT system has high resolution,large amount of data and high real time,and higher requirements for data transmission system.This paper mainly studies the high-speed and long-distance data transmission between the micronano CT detector and the computer.In terms of high speed data processing,FPGA has the advantages of high efficiency,high universality and modular design.So in this paper,the hardware design is realized by using FPGA + PHY way,relative to the ARM or single chip microcomputer is used to restore the physical and network communication between FPGA chip,not only reduces the system cost,save resource,but also improve the startup of the system.TCP and UDP are two protocols for Ethernet transport layer,each with its advantages and disadvantages.The TCP protocol is a reliable transport layer protocol connected to the face,and the data transmission is connected by three handshakes,which will naturally reduce the data transmission rate.UDP protocol is highly efficient,but it is an unreliable transport layer protocol.The sender is only responsible for sending the data and no matter whether the receiving party receives it,there will be a serious loss of package.So this article uses the GigE Vision protocols for data transmission,GigE Vision protocol is based on UDP/IP protocol,in the upper protocol on application layer to realize GVCP and GVSP protocol,by increasing the ACK and retransmission mechanism to ensure the reliability of transmission,and realizes the high speed data transmission at the same time.The system directly use Verilog HDL language programming to realize the data transmission of GigE Vision protocol in FPGA and communication with the upper computer software.The main control chip uses the cyclone III series of Altera company's cyclone III series EP3C5E144I7 FPGA chip.The Ethernet controller chip adopts the RTL8211 EG of Realtek company,and the 1000 M speed mode is realized through the GMII interface.The system includes hardware and software design,hardware design including circuit schematic design,and through Altium Designer software to complete PCB board drawing;Software design is mainly based on Quartus platform,use Verilog HDL to complete Gige vision protocol implementation,the use of the Modelsim simulation verify the correctness of the protocol sequence,at the same time use the upper machine design,combined with wireshark and other auxiliary software implementation on FPGA communicate with PC through the Gige vision transmission.(ideas: software design,simulation verification,board level verification)In view of the industrial CT,large quantities of data transmission distance,the designed system has the advantages of high reliability,strong anti-jamming capability,and give full play to the FPGA as the main control chip and GigE Vision as a transport protocol.