谱线弯曲对成像光谱仪辐射信号采集的影响

Effect of spectral curvature on signal acquisition of imaging spectrometer with prism dispersion in VNIR

为了研究谱线弯曲对棱镜色散成像光谱仪光谱辐射信号采集的影响，结合复合棱镜的色散特性，在可见近红外光谱区（400-1000nm）内，分析了当光谱偏离量为0．01、0．1和0．5d（d为探测器像元尺寸）时系统采集到的辐射信号与没有谱线弯曲情况下采集到的辐射信号的偏差，以衡量谱线弯曲下系统辐射测量的变化。实验结果表明：谱线弯曲引起的探测器上的光谱偏离会导致系统辐射信号采集发生变化。与没有谱线弯曲的情况相比，采集到的景物辐射信号住大气吸收带的边缘出现明显的偏差，且信号的差值随光谱偏离量的增大而增大；当光谱分辨率提高时，一些较弱的吸收峰附近也会出现明显的信号偏差。对于光谱分辨率平均为10nm的成像光谱仪，谱线弯曲引起的光谱偏离量应控制在0．3nm以内。

To study the effect of spectral curvature on the acquired radiant signal by imaging spectrometer with prism dispersion, the errors of acquired signal between with spectral offset 0. 01, 0. 05, 0. 1d（d is pixel dimension） and without spectral curvature was calculated by combining with the dis persive characteristics of composite prism in Visible-Near Infrared VNIR （400-1 000 nm）. The experimental results indicate that the scene radiant signal acquired by imaging spectrometer with spectral line bend exhibits distinct errors at the edges of atmospherical absorption bands compared with no spectral curvature, and the normalized signal errors increase with the spectral offset. When spectral resolution increases, there are distinct signal errors near some weak atmospherical absorption peaks. These results reported here suggest that spectral curvature should be no more than 0.3 nm for imaging spectrometer with 10 nm resolution.