| The Pseudo dual-energy X-ray theory has been widely applied in security check or material sorting fields, According to the different structure of the detector, dual-energy technology can be divided into true dual-energy and pseudo dual-energy, the pseudo dual-energy technology can be easily realized and widely used in practice. but although the Pseudo dual-energy X-ray theory has become mature, the X-ray detection technology at home is still far behind the world’s advanced level. At present most of the Pseudo dual-energy X-ray equipment applied in industrial detection field are imported from abroad, the equipment is expensive and bulky, this bring great financial burden to the enterprise. At the same time, large flat panel detector is not conducive to handling and installation. The development of computer technology has brought great change for Pseudo dual-energy X-ray technology. Pseudo Dual-energy X-ray digital imaging technology overcomes the disadvantages of the traditional film production. Compared with the traditional film production technology, dual-energy X-ray digital technologies have obvious advantages in image processing, storage, safety and other aspects.Based on the background of coal sorting requirements, the paper aims to establish an assembly, portable pseudo dual-energy X-ray digital imaging system, which can realize remote monitoring. The paper introduces the overall scheme, software and hardware design in detail, the paper also give a preliminary study on the material identification algorithm.By analyzes the advantages and disadvantages of several commonly used X-ray detection technology, this paper adopts the pseudo dual-energy X-ray technology to design this system. Aiming at the disadvantages of the current dual-energy detection technology, puts forward the digital, portable, mass and long distance data transmission solution. Followed the solution, the signal acquisition front-end scheme, the central control unit scheme, the image acquisition control and data transmission scheme are designed. The signal acquisition front-end consists of a plurality of the special structure of the pseudo dual-energy detector chip which is connected end to end in parallel, the length can be arbitrarily extended. Image acquisition control and data transmission is realized by computer and network communication.The hardware scheme, which is based on FPGA to build hardware platform is proposed. Considering the expansibility of the system, the hardware design of the whole system is divided into the power supply board, pseudo dual-energy detection board and main board, three circuit boards communicate with each other through wiring. The paper introduces the hardware design of the power module, pseudo dual energy detector module, multi-channel A/D module, FPGA minimum system module and network module in detail and put forward hardware anti-jamming measures for hardware design.Based on the pseudo dual-energy X-ray theory and the hardware design scheme, this study uses the Verilog HDL language to realize the function design of FPGA, mainly includes the function of pseudo dual-energy detector module, A/D module, Dual port RAM module and W5300 underlying drivers. During the environment of Visual C++, the PC control interface which can realizes parameters configuration and dual-energy image display is developed. Through the MATLAB environment, the relative atomic number can be obtained through the material identification algorithm. In addition, the paper adopts thickness correction algorithm which extended one-dimensional atomic number to two-dimensional plane to improve the material recognition accuracy.Finally, the paper debugs and tests the pseudo dual-energy X-ray digital imaging system in the laboratory environment. Experiments show that the system can successfully display the dual-energy gray image, material identification algorithm in this paper can accurately distinguish organic, inorganic and compound, the system meet the design requirements. |
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