摘要
光谱定标是确定光谱仪器各通道中心波长的过程,为了获取光谱辐亮度,通常需要对光谱仪器进行辐射定标,将光谱仪器输出的数值,映射为物理量——辐亮度。不同的光谱仪器的光谱响应不同,因此还需要在光谱定标过程中确定各个通道的光谱响应。光谱成像仪可以看成是多个光谱仪组成的,需要对所有点的中心波长和光谱响应进行定标。自第一台成像光谱仪诞生以来,其定标方法逐渐固定,通常需要采用光谱分辨率较光谱成像仪更高的单色仪输出准单色光进行光谱定标,其准单色光的光谱带宽远小于光谱成像仪的光谱响应带宽,可以将准单色光抽象为脉冲函数。根据脉冲函数的特性,改变准单色光的波长,扫描光谱成像仪的响应波长范围,是对光谱响应函数进行间隔采样的过程,通过光谱定标数据可以直接得到光谱成像仪的中心波长和光谱响应函数。随着技术的发展,探测器的灵敏度越来越高,光谱成像仪的分辨率也越来越高,为了完成光谱定标,对光谱定标需要的准单色光提出了更高的要求。然而准单色光的带宽越窄,其能量越低,获取满足信噪比要求的数据需要更长的时间,使定标的效率降低。从光谱定标的目的出发,结合准单色光和光谱成像仪光谱响应近似高斯函数的特点,通过理论分析,提出一种利用宽带定标光进行光谱定标的方法,可以有效减少光谱定标的步骤,提高定标的效率,适用于光谱成像仪的快速定标。该方法用于某星载高光谱成像仪的光谱定标,待标定光谱成像仪采用棱镜分光,具有色散非线性的特点,光谱分辨率在2~18 nm之间变化,同时存在较大的谱线弯曲,导致每个像元的中心波长都不同,需要对每个像元进行光谱定标。为了避免分视场定标导致的相邻视场中心波长不连续现象,将单色仪发出的准单色光的光斑照亮整个狭缝,狭缝和单色仪之间�
Spectral calibration is determining the central wavelength of each channel of a spectrometer.To obtain the spectral radiance,it is usually necessary to calibrate the spectrometer and map the output value of the spectrometer to a physical quantity radiance.Different spectrometers,The spectral response is different,so it is necessary to determine the spectral response of each channel during the spectral calibration process.The spectral imager can be regarded as a composition of multiple spectrometers,and the center wavelength and spectral response of all points need to be calibrated.Since the birth of the first imaging spectrometer,its calibration method has been gradually fixed.A monochromator with the higher spectral resolution is required,and its spectral bandwidth is much smaller than the spectral response bandwidth of the spectral imager so that quasi-monochromatic light can be considered a pulse function.According to the characteristics of the pulse function,changing the wavelength of the quasi-monochromatic light and scanning the response wavelength range of the spectral imager is a process of sampling the spectral response function at intervals..Therefore,the spectral imager’s central wavelength and spectral response function can be directly obtained from the spectral calibration data.With the development of technology,the sensitivity of the detector is getting higher and higher,and the resolution of the spectral imager is getting higher and higher.Higher requirements are put forward for the quasi-monochromatic light required for the spectrum calibration.However,the narrower the bandwidth of the quasi-monochromatic light,the lower its energy,and it takes longer to obtain data that meets the signal-to-noise ratio,which reduces the efficiency of calibration.In this paper,we combined the characteristics of quasi-monochromatic light’s spectral line type and spectral response function approximating to Gaussian function.Through theoretical analysis,a method of spectral calibration using wide-band quasi-monoch
作者
王建威
李伟艳
孙建颖
李兵
陈鑫雯
谭政
赵娜
刘扬阳
吕群波
WANG Jian-wei;LI Wei-yan;SUN Jian-ying;LI Bing;CHEN Xin-wen;TAN Zheng;ZHAO Na;LIU Yang-yang;L Qun-bo(The Key Laboratory of Computational Optic Imaging Technology,Academy of Opto-Electronics,Chinese Academy of Sciences,Beijing 100094,China;School of Instrumentation Science and Opto-electronics Engineering,Beihang University,Beijing 100191,China;School of Optoelectronics,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2022年第7期2013-2017,共5页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金重点项目(61635002)资助。
关键词
高光谱成像
谱线弯曲
光谱定标
Hyperspectral imaging
Spectral line bending
Spectral calibration
