Development Of Key Components For NIR Grating Spectrometer In Grain Quality Detector

China is a large agricultural country, and the development of agriculture forms a foundation for national development and social stability. Quality of agricultural products for rapid detection technology is in favor of guiding China's agricultural products converse from "production" type to "quality" type ,so it is of high importance for the agricultural development. With the advantage of better accuracy and repeatability, fast and clean characteristics, the near infrared(NIR) spectroscopy analysis method has been used in many trades such as agriculture, food, petrochemical, chemical industry, etc.The research work in this paper was supported by branch project "NIR rapid detection system for internal quality of grain" of key project named "Research on detection technology for quality of agricultural products and technology commercialization for equipments development" (No: 2006BAD11A12) in the technology pillar program in the 11th five-years plan period. The main research work can be concluded as following:1,The principle of fixed grating and charge-coupled device (CCD) of the NIR spectrometer is described in detail, and we have developed the linear array CCD drive circuit and the spectrum signal acquisition circuit.2,A single-chip microcomputer-based control of NIR light source is developed, and the control precision meet the requirements of the system. We have achieved a CCD cooling function to provide a stable working environment, and have completed the sample turntable control system.3,The development of Software includes the temperature control and the light control program based on MCU and PC, and the spectral data processing and analysis program, and so on. The main studies of Spectrum Analysis Technique include the first derivative spectra, wavelet transform filtering, partial least squares (PLS),etc.4,Based on the relevant experiments of wheat samples, we have tested the accuracy and stability of the NIR instrument for rapid detection of grain quality, and verified the feasibility of testing grain quality by the NIR spectrometer.5,Through the comparison of the MPA spectrometer from the BRUKER company, we are aware of the existence of a certain gap in the accuracy. The first reason is based on the measuring principle. The second is that the key components of the equipment abroad have better performance then ours. Finally, there are big gap in the processing technology. However, our spectrometer can meet the demand for certain practical applications with a big Price advantage.