| In recent years,technology has developed rapidly and rapidly,near-infrared spectroscopy technology has been widely used in its own unique advantages: simple and convenient detection,no damage,high efficiency,rapidity,no pollution,rich information,real-time online analysis,etc.It is widely used in scientific experiments,industrial manufacturing,agricultural production,petrochemical,food safety testing,pharmaceutical monitoring,human monitoring and other fields.Near-infrared spectroscopy is a key technology that can effectively analyze different materials.In order to apply this technology to more places and environments,and to detect more kinds of materials,people have developed different kinds of near-infrared.Spectroscopic instrument,such as there are commonly used filter type,dispersion type,modulation spectrum type near-infrared spectrometer,etc.And various types of spectrum instruments have their own advantages and disadvantages.However,with the advent of Digital-Mirror Device(DMD),Digital Micro-mirror Devices Based Hadamard Transform Near-infrared Spectrometer has become a research hotspot for researchers.The spectroscopic instrument uses a grating as a spectroscopic component,a digital micromirror(DMD)device for spectral selection,and a single-point InGaAs detector to receive the modulated spectral signal to form a Digital Micro-mirror Devices Based Hadamard Transform Near-infrared Spectrometer.Digital Micro-mirror Devices Based Hadamard Transform Near-infrared Spectrometer with no moving parts,it can achieve the perfect combination of high speed,high resolution,high signal to noise ratio and strong environmental adaptability,and does not require mechanical movement when changing the template.Enter the appropriate template.This paper focuses on the Digital Micro-mirror Devices Based Hadamard Transform Near-infrared Spectrometer.In the first chapter and the second chapter,the basic background of the subject and related application principles are introduced.In the third chapter,the method based on the maximum correlation coefficient of the same sample absorbance curve is used to calibrate the wavelength consistency of the two spectrometers,so that the accuracy of the wavelength meets the requirements during the model transfer,and the model can be directly transferred between the two spectrometers.The difficulty of absolute wavelength calibration for each spectrometer is avoided.Secondly,the spectrometer was used to measure the absorbance of medical alcohol and another material.The experimental results before and after the wavelength normalization were compared to verify the feasibility of the method.Finally,the main performance indicators of the spectrometer were tested,indicating that the spectrometer performance is stable.In the fourth chapter,the stripe scanning method is compared with the Hadamard transform scanning method,and the stray light in the Digital Micro-mirror Devices Based Hadamard Transform Near-infrared Spectrometer is analyzed by Zemax software.It is concluded that stray light is generated when the DMD is in the "off" state,and stray light is also generated in the window before the DMD,and both of these stray light will enter the detector to affect the test result.In the last chapter of the thesis,the overall work of this thesis is summarized and forecasted. |
