依据实验室辐射定标实验，校正反射式拼接 CCD 相机由渐晕现象引起的图像非均匀性。通过分析反射式拼接CCD 相机成像非均匀性产生机理，明确焦平面辐照度非均匀性是造成相机图像非均匀性的主要原因；分别进行“单片CCD 辐照度响应度定标”和“整机均匀性定标”实验；依据定标结果所得出的入射辐射亮度和在该亮度下每个像元实际接收到的辐射照度之间的关系，设计校正算法，得出每个像元的渐晕校正因子，实现渐晕图像非均匀性校正。校正结果显示：在一定入射辐射亮度范围内，原始积分球定标渐晕图像的非均匀性大于16％，用校正因子校正后，输出图像非均匀性下降到1％以内。经过非均匀性定标和校正的相机用于外场成像也取得了符合工程需要的满意效果。
According to the radiometric calibration experiments in laboratory,the reflector-based mo-saic CCD camera’s image non-uniformity caused by vignetting phenomenon was corrected.Firstly, the image un-uniformity reasons of reflector-based mosaic CCD camera are analyzed,and the irradiance deviation received by different CCD pixels in focal plane is the essential reason for images’non-uni-formity. Then, the CCD pixels ’ irradiance responsivity calibration experiment and the whole camera’s non-uniformity calibration experiment were carried out in the laboratory,and the relation-ship between each pixel’s receiving irradiance and camera’s incident radiance was built.Lastly,a cor-rection algorithm is put forward based on the above relationship to calculate CCD pixels’correction factors,and the correction factors were used to correct the vignetting image.The correct experiment indicates that,within a certain range of incident radiance,the non-uniformity of original calibration images are above 1 6%,and after correction,the values decreased to 1% or less.Besides,the correc-tion factors were used to correct the images of outdoor experiments and it works very well.
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