测绘相机焦平面CCD交错拼接中重叠像元数计算  

Calculation of overlapping pixels in interleaving assembly of CCD focal plane of mapping camera

作　　者：郭疆[1,2] 龚大鹏[2,3] 朱磊[2] 孙继明[2] 邵明东[2] 

机构地区：[1]吉林大学机械科学与工程学院,吉林长春130022 [2]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [3]中国科学院大学,北京100049

出　　处：《光学精密工程》2013年第5期1251-1257,共7页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.60507003)

摘　　要：针对采用焦平面CCD交错拼接方式的测绘相机会由于存在交会角而产生视场拼接漏缝问题,本文在考虑交会角和相机无侧摆的前提下提出了一种焦平面CCD重叠像元数算法。首先,根据测绘相机成像原理建立了前视相机成像模型,分析了产生视场漏缝的原因。接着,推导出在CCD数量为奇数和偶数两种不同拼接形式下的地面视场重叠及漏缝大小的数学表达式,进而得到了不产生漏缝时CCD片间最小重叠像元数计算公式,并对误差进行了分析。最后,将该算法应用于工程算例,并对比了地球曲率对计算结果的影响。通过算例得到了各CCD片间视场漏缝及最小重叠像元数,其最大值分别为1 141.491μm,115个。应用本文方法可以近似计算应用交错拼接法的测绘相机焦平面前后排CCD的最小重叠像元数,误差小于1pixel。Imaging gaps will appear in the field of view for a mapping camera due to the convergence angle when it uses a interleaving assembly of focal plane.In order to solve the problem above,an algorithm of minimum overlapping pixels was proposed by considering convergence angle and without camera pitch.Firstly,an imaging model for the front view camera was established according to the imaging principle of mapping camera.The reason that imaging gaps appear was analyzed.Then,the mathematical expressions of imaging gaps and overlaps of odd and even quantity CCD assemblies were derived,the formula for computing the minimum number overlapping pixels between adjacent CCDs that can avoid the imaging gaps was obtained,and the error was analyzed.Finally,the algorithm was applied to an engineering example,and the effect of earth curvature was analyzed.The instance shows that the imaging gaps and the minimum number of overlapping pixels in the engineering instance are 1 141.491 μm and 115 in maximum respectively.It indicates that the proposed algorithm can calculate the minimum number of overlapping pixels of the mapping camera and the theoretical error is less than 1 pixel.

关 键 词：测绘相机 焦平面 CCD 交错拼接 重叠像元数 

分 类 号：V447.3[航空宇航科学与技术—飞行器设计] TN386.5[电子电信—物理电子学]