机械快门滤光片式多光谱成像仪相对定标方法研究

Study on the Relative Radiance Calibration Method of Large Array Filter-Type Multispectral Imaging System

大面阵滤光片阵列多光谱成像仪采用了全帧转移大面阵探测器,并利用机械快门保证采集数据时不发生拖尾现象,但由于机械快门开合时间的不稳定性,使多光谱成像仪数据出现区域间的亮度不均匀,而且还会造成彩色图像偏色条带。故提出了一种基于目标辐射一致性的相对辐射定标方法,利用图像重叠部分的辐射特性,计算光谱图像的辐射矫正因子,对拼接图像的非均匀性进行矫正。并利用差分评价矫正效果。最后对多光谱相机采集的外场实验数据进行处理和矫正,结果表明,该方法可以很好的矫正单色拼接图像区域间的非均匀性,并可以消除彩色合成图像中的偏色条带;适用于有重叠部分的图像拼接,并且对于拼接误差不敏感。

The full frame transfer sensor with large array is used in the large array filter-type multi-spectral imaging system,and a mechanical shutter is employed to avoid the images blurred.But the mechanical shutter is unstable,reducing the mosaic images＇ uniformity and producing RGB images＇ color bar with bias.The paper proposed a method of relative radiance calibration based on objects＇ radiance coherence.The correction factors were obtained by the different images with same objects,and used to correct the images based on the first frame.The mosaic images＇ first difference was introduced to appraise the images uniformity before and after correction.The field data were corrected by this method,which indicated that the method could correct the non-uniformity of mosaic images and the color bar with bias.The method is unsensitive to the accuracy of mosaicking,and can be used widely.