| With the in-depth study of infrared radiation characteristics measurement and the rapid development of infrared technology applications,the infrared radiation characteristics of space targets have received more and more attention.For the longrange space target,its temperature is one of the important parameters to show the working state and performance of the target,which has important reference value for judging its motion state and predicting its situation development.The infrared radiation characteristics of the long-range space target can directly reflect the physical characteristics of the target.The infrared radiation characteristics of the target can be obtained.Combined with the corresponding radiation calibration method,the radiation brightness and temperature of the target can be quantitatively inverted,and the depth recognition of the space target can be realized.At present,the commonly used infrared radiation measurement system for the target is to use the full-band radiation brightness integral measurement of the corresponding response band of the detector.However,this method is based on the assumption that the target emissivity is a fixed value measurement,and only the relative information such as the apparent radiation brightness and apparent temperature of the target is measured,which cannot meet the true temperature measurement of the target.Multi-spectral radiation thermometry can use the spectrum of the target to obtain the real temperature information of the target.Compared with the commonly used single-band radiation characteristic measurement method,it has obvious advantages and high temperature measurement accuracy.Specifically,this paper mainly completed the following six aspects of research work:(1)The infrared detection technology,multi-spectral radiation temperature measurement technology and target radiation characteristic measurement technology are deeply investigated.The basic theory of infrared radiation and the theoretical model of common radiation calibration methods are introduced,which lays a solid theoretical foundation for the subsequent spectral radiation temperature measurement methods.(2)A mid-infrared multi-spectral radiation temperature measurement system is designed,and the device selection is theoretically deduced in detail based on the technical indicators.The core instrument of the multispectral temperature measurement system is a slitless grating spectrometer,which can greatly reduce the requirements for tracking and stable accuracy of space targets.The mid-infrared multi-spectral radiation temperature measurement system is an important prerequisite for the measurement of target temperature,which is prepared for the subsequent internal and external field experiments.(3)Combined with the shortcomings of the commonly used calibration methods based on gray value and target radiance,in order to solve the problem that the response rate in the calibration model will change with the change of imaging distance,which leads to the decrease of temperature measurement accuracy,a radiance spectral radiation temperature measurement method based on distance correction is proposed.The infrared radiation calibration model is improved from the spectral dimension,and the distribution trend of the target spectrum is fitted with the blackbody radiation curve.The response rate after distance correction is used to ensure high-precision measurement of the target temperature.(4)Aiming at the influence of unknown target emissivity on the temperature measurement model,a multi-band radiation temperature measurement method based on target spectrum is proposed.This method is based on the higher spectral resolution in the image,assuming that the emissivity of the target between adjacent spectral channels is equal,and the temperature measurement model is constructed by the ratio of the data of adjacent spectral channels.It overcomes the disadvantages of the commonly used calibration model that the target emissivity is assumed to be constant and is suitable for all detection distances,which leads to large temperature measurement error.In theory,the influence of distance and target emissivity can be eliminated,and then the true temperature measurement of the target can be realized.(5)The complex and changeable environment will seriously affect the accuracy of temperature measurement.Aiming at the influence of ambient temperature on the multiband radiation temperature measurement model,the method of correcting the bias term in the temperature measurement model by using the ambient temperature is introduced,so as to reduce the influence of ambient temperature on the temperature measurement model and improve the temperature measurement accuracy of the target.(6)For the field experimental data,the signal-to-noise ratio of the target spectral image at different distances and different temperatures is calculated.Combined with the inversion error of the two temperature measurement methods,the relationship between the signal-to-noise ratio and the temperature measurement accuracy is analyzed.In this paper,the multi-spectral infrared radiation temperature measurement method for small targets is studied in depth.A mid-infrared multi-spectral radiation temperature measurement system is developed and a lot of experimental work has been carried out.The experimental results show that the average error of temperature measurement is 0.8851 %,and the overall temperature measurement error is within 3 %.If the laboratory calibration coefficient is fixed,the average temperature measurement error is about 12 %,and the maximum temperature measurement error is about 25 %.It is obvious that this method can improve the temperature measurement accuracy.The average temperature measurement error of the multi-band radiation temperature measurement method based on the target spectrum proposed in this paper is 2.0226 %in the external field environment,and the maximum temperature measurement error is around 3 %.After the bias correction,the average temperature measurement error is1.1818 %,and the overall temperature measurement error is within 3 %.The bias correction model can effectively reduce the temperature measurement error.The research results of this paper have important reference value for the design of multispectral radiation temperature measurement system and have certain practical value for the engineering application of target spectral radiation temperature measurement. |
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