Remote Sensing Experimental Study On Shortwave Infrared Radiance Directivity Of High Temperature Target

Study on the directionality of electromagnetic radiation of ground objects is an important content and difficulty of multi-angle remote sensing.The research on temperature inversion method has important theoretical significance and practical value for remote sensing resource survey,environmental monitoring and disaster warning.For the high-temperature target temperature inversion using short-wave infrared,the directivity of emissivity and emissivity is the key factor that restricts the accurate improvement,research in this area has not been reported yet.This paper first theoretically deduces the multi-angle observation of the high-temperature target of the non-full field of view,and determines the relationship between the spectrometer reading and the true radiance of the high-temperature target.Secondly,burning bamboo charcoal as the low-temperature target of small surface,using ASD FieldSpec3 to observe it at different angles in darkroom conditions.The observation data of multiple angles cannot be acquired simultaneously using only one spectrometer,and the temperature of the high temperature target changes significantly when observed at different angles.This paper proposes a cooling model to calculate the reference radiance₀ of multi-angle observation.This paper proposes a concept-radiation ratio?multi-angle radiance/reference radiance₀?,used to study the directional law of high temperature targets,and use variance analysis for radiance data and radiance ratio data to determine the directional wavelength range and significant level.The study found that the radiance ratio is suitable for regression analysis.For the data of high-precision fitting wavelength range,the determination coefficient of linear model and nonlinear model is statistically significant,which can explain the saliency of different angles of radiance than data,but for The data of the weakly fitting wavelength range is not convincing to determine the coefficient.Therefore,in order to verify the difference of data,a variety of observation schemes to overcome the cooling factor were designed,and the variance analysis was performed on the radiance data and the radiance ratio data to determine the directional wavelength range and significant level,and to test the radiation.Brightness is more reasonable than this concept.The results of variance analysis show that the radiance L and radiance of the high temperature target are highly significant in the directionality of the wavelength???1350nm,2500nm?.The curve fitting results show that the cooling model in the form L=f?t?=(6₁·exp(?7₁·t?+(6₂·exp(?7₂·t?can fit the law of radiant brightness with time,and the determination coefficient of all samples is greater than 0.97.The cosine function,the Fourier series,and the normal distribution probability density function can achieve a high-precision fitting of the radiance ratio with angle in the wavelength???1650nm,2500nm?.The results of analysis of variance and regression analysis show that the directionality of the high temperature target in the range of wavelength???1350nm,2500nm?is highly significant.It is worth noting that this paper finds a probabilistic relationship between the radiance and brightness of high-temperature targets with angle changes,and provides data support and preliminary theoretical basis for further study of the physical mechanism of directionality of high-temperature target radiation.