针对红外超光谱干涉光谱仪的技术特点,分析其探测器非线性响应的形成机理,仿真含有高阶非线性误差的干涉数据,并研究二、三阶非线性响应对光谱的影响;提出一种迭代方法,即通过交叉迭代使光谱带外畸变最小,从而确定校正系数进而校正非线性响应;通过获取不同温度黑体观测的干涉数据,用交叉迭代法校正实测数据并复原光谱,将未吸收波数光谱响应与黑体辐亮度进行拟合。结果表明:二阶非线性响应主要影响带外数据,三阶非线性响应主要影响带内数据,仅校正二阶非线性响应时,光谱带内数据仍会有残留误差;交叉迭代法可以校正探测器的非线性响应,且三阶非线性校正的精度比二阶的提高了约7.26%;校正后的拟合优度比校正前的提高了约0.4%,校正后的干涉数据更准确。

Abstract In consideration of technical characteristics of the infrared hyperspectral interferometric spectrometer, we analyze the formation mechanism of nonlinear responses of its detector. The influences of second-order and third-order nonlinear responses on spectra are studied by means of simulating interference data with high-order nonlinear errors. An iterative method is proposed to minimize the out-of-band distortion by cross-iteration, thus the correction coefficient is determined to correct the non-linear responses. The interference data observed by the blackbody at different temperatures are corrected by the cross-iteration method, and then the spectra are recovered. The spectral response of the undisturbed wavenumber is fitted to the blackbody radiance. The results show that the second-order nonlinearity response has a major impact on the out-of-band data, while the third-order nonlinearity response mainly affects the in-band data. So the in-band data will still have residual errors when only the second-order nonlinear response is corrected. The cross-iterative method can correct the nonlinear response of the detector, and the accuracy produced by the third-order nonlinearity correction is improved about 7.26% compared to the second-order correction. The corrected goodness of fit is improved by about 0.4%, and the corrected interference data are more accurate than before.