谱线弯曲破坏了色散型成像光谱仪光谱辐射能量采集的一致性, 采用插值的办法对系统采集到的辐射能量数据依据无偏离波长定标数据重新采样, 可以提高光谱辐射测量的一致性。 选择恰当的插值采样方法尤为重要, 直接影响校正后辐射能量偏差的剩余量, 决定了校正效果的好坏。 采用常用的线性、 三点二次多项式、 四点三次Lagrange、 五点四次Lagrange、 三次Hermite和三次样条插值方法对存在光谱偏离的像元采集到的辐射能量数据进行重新采样, 比较采样后辐射能量剩余偏差, 结果表明： 四点三次Lagrange插值和三次样条插值的校正效果明显好于其他四种方法。 对于系统光谱偏离量10% Δλ(Δλ=5 nm), 辐射能量归一化偏差PV=0.06, 插值校正后PV<0.022, 采用其他四种方法校正后PV均大于0.035。 另外, 光谱分辨率较低时(Δλ>5 nm), 四点三次Lagrange插值略优; 光谱分辨率较高时(Δλ<5 nm), 三次样条插值略优。

Spectral curvature destroys the co-registration of the spectra measured by dispersion imaging spectrometer.Using interpolation to re-sample the measured spectra at the non-offset mid-wavelengths can mitigate the spectral misregistration.It is very important to select an optimum interpolation method.The performances of six common interpolation methods are evaluated by comparing the residual errors in the corrected spectral radiance.The results indicate that, four-point cubic Lagrange interpolation and cubic spline interpolation are better than other four interpolation methods (linear Interpolation, three points quadratic polynomial interpolation, five points four-order Lagrange interpolation and cubic Hermite interpolation).For spectral offset of 10% Δλ(Δλ=5 nm), the normalized errors in measured spectral radiance is PV=0.06, that is reduced to PV<0.022 after interpolation with cubic Lagrange interpolation or cubic spline interpolation, but for other four methods they are PV>0.035.Furthermore, for lower spectral resolution (Δλ>5 nm), cubic Lagrange interpolation is a little better than cubic spline interpolation; while for higher spectral resolution (Δλ<5 nm), cubic spline interpolation is a little better.