推扫型高光谱数据光串扰校正方法研究

Analysis of Optic Crosstalk Correction for Pushbroom Hyperspectral Data

串扰是成像光谱仪非理想成像特性中的一种,分为电串扰和光串扰,它广泛存在于现有的成像光谱仪之中。推扫型高光谱数据的光串扰使目标像元受到临近像元的影响,目标像元光谱曲线发生变化,图像的清晰度降低。基于推扫型成像光谱仪的成像原理,提出一种针对推扫型高光谱数据的光串扰校正方法。从高光谱数据中选取包含白色定标布地物的区域作为参考数据,通过行间差值方法得到所有白色定标布像元产生的总光串扰量;对总光串扰量进行拟合以抑制噪声,并通过递归方法计算单个白色定标布像元所产生的光串扰量;使用该串扰量对整景数据进行光串扰校正。选用三景不同地物类型的PHI数据进行光串扰校正,结果显示,校正后数据的光串扰现象得到明显的抑制,数据质量在光谱维和空间维均得到有效提升。在光谱维,由光串扰引起的光谱曲线变化得到校正;在空间维,图像清晰度提高50%以上的波段数占总波段数的83%。校正方法直接从高光谱数据本身提取光串扰量,并对数据光串扰现象进行校正,不依赖于其他外部数据,且适用于不同的地物类型。该光串扰校正方法亦对实验室测定成像光谱仪的光串扰量具有借鉴意义。

Based on the imaging process of pushbroom hyperspectral imager ,a correction method for optic crosstalk was devel-oped .An area that has white calibration target was selected as reference data .The target pixels crosstalk quantity was gained using the subtraction between the two lines of reference data ,and it was fitted to restrain noise .Using recursion method , crosstalk quantity of single pixel was calculated from the fitted function ,and it could be used to correct the optical crosstalk of the whole data .Three PHI (pushbroom hyperspectral imager) data which have different ground scene were corrected .It was showed that optical crosstalk in corrected data is lightened obviously ,and the data quality is improved effectively in both the spectral dimension and spatial dimension .The spectral changing caused by optical crosstalk is also corrected ,and the bands with definition increased more than 50% accounts for 83% of the total bands .Optic crosstalk is obtained form hyperspectral data it-self which is independent of other data source .It is proved that the correction method is valid ,and it is applicable for different ground type .The correction method also provides a way to measure the optic crosstalk of hyperspectral imager in the lab .