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【2006博】多模态CCD相机系统(MADC)构像方式和数据处理研究
【作者】 卫征 【导师】 童庆禧;郑兰芬 【 学位年度 】 2006 【论文级别】 博士 【关键词】 航空数字遥感,面阵CCD,遥感数据处理,POS系统 【Key words】 aerial remote sensing, array CCD, POS, remote sensing image processing 【中文摘要】 研制大面阵CCD航空数字相机系统是当前国际航空遥感技术发展的一个重要方向,对于推动我国航空遥感技术的发展和航空摄影测量设备的数字化进程,提高国内航空数字遥感技术的水平、降低对国外同类产品的严重技术依赖、满足国内对高精度、高分辨率航空遥感影像的迫切需求有着重要的意义和极大的视场价值。 中科院遥感所高光谱遥感研究室研制出多模态航空数字相机系统(MADC)。MADC系统由3台4K×4K的大面阵CCD数字相机组成。根据这些相机不同位置和姿态的组合,可以形成宽视场、多光谱和立体成像3种模式。该系统能够与空间定位定向系统(POS)连接,根据特制的快门控制系统可以实现多台相机按照设定时间间隔的同步曝光,并同时与POS数据按时间进行关联。 因此,与常规的航空数字摄影设备比较,除了数字成像外,多模态、多光谱可选以及与飞机位置姿态测量系统链接是MADC系统的重要特点。 本文在国内首次针对MADC系统各种工作模式的成像机理、该系统的标定及利用POS数据对获取影像进行几何精校正处理等方面进行了详细研究。论文的主要研究内容包括: (1)对MADC系统的成像模式进行简化,抽象形成MADC系统成像的基本(组合)模式,并对其成像几何关系进行了详细的分析研究,得出了关于MADC系统成像、乃至涉及多角度遥感成像机理的一系列重要结论和推论。 (2)对MADC系统在实际作业时受到的几何干扰因素进行了研究分析,尤其是给出了大气折射、地面起伏、地球曲率等因素对面阵CCD成像的干扰模型,得出了大气折射和地球曲率的干扰不容忽视的结论。 (3)针对MADC系统的检校,研究了镜头的畸变改正模型和影像的畸变改正。基于单片后方交会,给出了基于地面控制点和POS数据的各相机光轴偏斜角度和前节点空间位置的解算方法。 (4)研究了POS数据与线阵CCD推扫数据和面阵CCD拍摄数据的关联,给出了针对面阵CCD的关联方案,解决了变多中心投影影像为单一投影中心影像的难题。 (5)研究了MADC系统多光谱模式和立体成像模式的成像效果,评价了滤光片的工作效果以及提出了多种可能的立体成像方式。 【Abstract】 It is an important direction of international remote sensing technologies to develop aerial large array CCD digital remote sensing system. The development and digital progress of national aerial digital remote sensing technologies and photography devices will be greatly pushed about, and sharply descend the depends on foreign products of the same kind. What’s more, the rapid improvement of China society and economics urgently requires large amount of high precision and high special resolution remote sensing images. Aerial large array CCD digital remote sensing system will just meet the requirement as it can obtain surficial information high availability. In order to follow the currency, hyperspectral research group of Instituteof Remote Sensing Application, CAS pushes out a multi-mode airborne digital camera system, what is called MADC for short. MADC system is combined with 3 digital cameras, which each has a large array CCD as 4K×4K. With different position and pose, the cameras can be combined to form different imaging modes, which are Wide Field, Multispectral, and Stereophotography mainly. MADC system can also be linked with Position and Orientation System (POS), and its cameras can be controlled to expose synchronistically associating with POS data according to regular time set by shutter control system. POS system can be seemed as the combination of GPS and IMU (Inertial Measurement Unit), and its data can show the spatial position and pose of aerial platform. To do geometric correction of remote sensing images aiding with POS data, it can get rid of the limitation of ground control points (GCP). So combined with normal aerial digital photographic devices, multi modes, multi spectral, and association with POS are the important characters of MADC. This paper studies the imaging mechanism of each working mode of MADC, the calibration of MADC and the methods to correct MADC data with POS information for the fist time at home. The main contents include 7 aspects as showed below. (1) Simplifying the geometric relationship of MADC’s cameras. By abstracting, the thesis gets the basic imaging mode of MADC and does detailed researches to the geometric of spacial projection. And the paper gets some important conclusions and inferences about MADC imaging, and even about normal mulit-angualer remote sensing. (2) Analyzing the geometric factors, which are actually influencing imaging while MADC system working. The paper promotes interference models of atmosphere infraction, hypsography and earth curvature, and gets the conclusion that the interferences of atmospheric infraction and earth curvature are not neglected. (3) Aiming at calibrating MADC system, the paper studies the distortion models of lens and does distortion correction of images. Basing on resection of single photo theory, the thesis gives methods to calibrate the pose of cameras’ optical axis and spacial position of pre-node of the lens by GCP and POS data. (4) Researching how to relate POS data to image lines of linear CCD or images of array CCD, giving the relation methods for array CCD images, and resolving the problem of change mulit-center projection to single center projection. (5) Studying the imaging effects of MADC multispectral mode and stereophotography mode, estimating the working results of optical filtering chips of MADC, and putting forward several possible stereophotography models.
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