Research On Thermal Infrared Imaging Spectrometer Calibration Technology

Due to the limited technical conditions,the development of thermal infrared hyperspectral imaging technology is relatively slow,In recent years,with the development of technology,the development and application of thermal infrared hyperspectral sensor has attracted the attention of all countries and institutions.This subject is mainly based on the thermal infrared module of imaging spectrometer of a certain type aircraft mission,this paper mainly studies on the spectral calibration,radiometric calibration and data processing of the thermal infrared module of imaging spectrometer.Spectral calibration is the measurement of the influence of the incident radiation wavelength on the response of the imaging spectrometer,ensure the spectral center wavelength position,spectral resolution and spectral sampling interval of the imaging spectrometer.Radiometric calibration is making the quantitative relationship between the digital output(DN value)and the pupil luminance.It is very necessary to carry out precise spectral calibration of imaging spectrometer in the quantitative analysis of remote sensing information using imaging spectrometer.The spectral response function at the central wavelength of each spectral channel can be obtained by using the results of spectral calibration and radiometric calibration.The spectral response function at the central wavelength of each spectral channel can be obtained by radiometric calibration,That is to say,the target data can be obtained by using the spectral data observed by the imaging spectrometer.the system carries out the spectral calibration,radiometric calibration and data preprocessing to meet the actual needs of the project on the basis of the research and simulation design,Spectral calibration method is divided into characteristic spectrum method and monochromator wavelength scanning method,The characteristic spectrum method is used to estimate the central wavelength of the spectral system by using the material with the characteristic spectrum absorption peak as the light source,the scope of application is narrow.The monochromator wavelength scanning method can obtain the spectral response curve of each detector spectral channel,and according to the central wavelength and spectral resolution can get spectral channel spectral response curve,The calibration accuracy of this method is high,and it can be calibrated in the whole wavelength range.In this paper,the wavelength scanning method is used to measure the thermal infrared module of the imaging spectrometer.The calibration precision is better than 1.7069 nm.Radiometric calibration is divided into relative radiometric calibration and absolute radiometric calibration,the calibration source used in laboratory is blackbody,The thermal infrared image of relative calibration with two-point correction and four point correction method,the final result of relative error is 0.62%,and the absolute radiometric calibration error is less than 1.54%.This paper also studies the image preprocessing technology,introduces the mechanism,detection and compensation method of the blind element in the image.Proposing a method of difference equalization is proposed to remove the non-uniformity in hyperspectral images and obtain good results.Also proposing a method of removing the residual noise,which can be applied to the field of high sensitivity applications and no scene restrictions.