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A Research Of The Key Techniques In NIR Micro Spectrometer

Posted on:2017-05-23Degree:MasterType:Thesis
Country:ChinaCandidate:M XieFull Text:PDF
GTID:2272330485988262Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
With the advantages of enormous information and easy accession, the near infrared spectroscopy analysis has been widely used in many different fields such as food quality testing, biomedical analysis, fiber optics sensing and aerospace exploration. However, the traditional NIR spectrometer is not suitable for industrial applications because of its huge size. To solve this problem, the NIR micro spectrometer was invented. The micro spectrometer has the advantages of small size and quick response, which makes it more and more popular in industrial real-time analysis.In this thesis, the future of NIR micro spectrometer was detailedly investigated, and the domestic and foreign development was comprehensively introduced. In order to develop a high resolution, small size NIR micro spectrometer, the following work was conducted in this thesis.Firstly, the basic theory and the structure of NIR micro spectrometer were introduced in detail, then specifically analyzed the principle of the optical system. After careful introduction of the main performance parameters, the determination of those parameters was fully analyzed.In the research of the micro spectrometer optical system, two common optical structures were compared and analyzed, then the flat-field concave grating structure was chosen to improve the wavelength resolution. The aberration of flat-field concave grating was studied in order to optimize the grating structure. The simulation results indicated that the resolution of the optimized concave grating was better than 1 nm.Then the electronic circuit and the software algorithm design were conducted in this thesis. The core chip is a Altera FPGA, which drives the linear CCD, controls the AD conversion, stores the digital data and transmits the spectrum data to the PC. In the design of the software, the hardware driver and the user interface was firstly finished, then designed the denoising algorithm to eliminate the noise in the spectrum raw data. What’s more, a new algorithm to improve the spectrum resolution was designed, which successfully improved the resolution without any changes on the hardware.At the end of this thesis, the optical system, the hardware circuit and the software were put together to conduct whole system debugging. The results indicated that the performance of the micro spectrometer design in this thesis was as good as that of the commercial micro spectrometers in the markets.
Keywords/Search Tags:NIR analysis, micro spectrometer, resolution-improving algorithm, flat-field concave grating
PDF Full Text Request
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