中国科学院遥感与数字地球研究所-高光谱遥感应用技术研究室推荐内容
【2012博】航空数字相机系统参数检校与自动拼接关键技术研究
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【作者】 孙韬 【导师】 童庆禧 【 学位年度 】 2012 【论文级别】 博士 【关键词】 高光谱遥感，光谱混合模型，光谱诊断，目标探测，蚀变信息提取 【Key words】 Aerial Remote Sensing, Image motion compensation, Multi-Digital Cameras System, Geometric Calibration, Tilt-Shift, automatic mosaic 【中文摘要】 当今，随着航空摄影测量技术的逐步发展，航空数字相机系统在测绘、遥感等领域中扮演着越来越重要的角色。同时数字摄影测量的光学载荷正向着数字化、宽幅CCD面阵、结合POS系统以及多数字相机成像组合的方向发展，对于航空摄影测量数据处理流程提出了很多新的问题和挑战。在相机检校和影像预处理流程上，单数字相机系统已经形成了相对较为完善的处理流程，有大量的参考文献和技术标准。但是相对于多数字相机系统，由于技术流程相对较为复杂，因此使用传统的参数检校和预处理的方法存在的问题较多。 本文从航空数字相机参数检校和多幅影像自动拼接的角度出发，重点从以下几个方面进行了研究和论述： 1. 分析了在我国发展航空遥感和航空数字相机系统的重要意义；研究和总结了国内外多种成熟航空相机系统的构建模式和几何成像原理；介绍了多数字相机系统的系统组成、工作原理和试验情况；提出并分析了参数检校在航空数字数字相机系统中的重要性，分析总结了多数字相机系统对参数检校和自动拼接所提出的新问题。 2. 总结分析了像移产生的原因和像移补偿的基本要求，设计了一种基于微米促动器的后推式像移补偿设备，通过实验验证了该设备能够有效的消除像移。接下来，分析了机械后推式像移补偿方法存在的一大问题，即可能造成补偿瞬间相机内方位元素的改变。因此通过公式推导，对像移补偿所产生的内方位元素改变对后续处理的精度可能产生的影响进行了初步的定量分析，并提出了一定的解决方案。 3. 研究了多数字相机系统和单数字相机系统在参数检校上的差异，设计了多数字相机系统参数检校的流程。在此基础上，构建了室内、室外三维定标场，提出了多数字相机系统准内方位元素的概念，研究了多数字相机系统内方位元素、准内方位元素、畸变模型、曝光瞬间外方位元素改正的检校算法和流程。 4. 详细分析了一种全新的基于移轴成像原理的多数字相机系统，构建了原型验证系统，并对其进行了室内参数检校评估。在检校实验中，分析了新系统和传统多数字相机系统的差异，形成了针对移轴相机的参数检校流程，解决了新系统对参数检校提出的许多问题。最后，通过室外的飞行试验，验证了这种全新的基于移轴成像原理的多数字相机系统可以避免许多传统多数字相机系统的弊端，能够更有效的发挥多数字相机系统的优势。 5. 对多数字相机系统单组影像自动拼接的关键技术进行了研究，研究了基于准内方位元素的图像变换，SIFT特征匹配算子。同时，在改进RANSAC的基础上，研究了一种针对存在较大畸变的影像上，高效自动的剔除误匹配点和最优变换模型估计的综合算法。最后，研究了线性辐射归一化的基本原理，提出了一种基于SIFT的自动辐射归一化新方法。 通过对以上的航空相机系统参数检校和自动拼接关键技术进行的重点研究和分析，本文研究解决了像移补偿的一些关键技术；形成了针对多数字相机系统参数检校的算法和流程；分析研究了基于移轴成像原理的多数字相机系统及其检校流程；研究解决了多数字相机系统单组影像自动拼接的一些关键技术。本文的研究十分有利于推进航空数字相机系统，特别是多数字相机系统在航空遥感领域的发展。
【Abstract】 Nowadays, with the development of the aerial photogrammetry, airborne digital camera system played more and more important role in the surveying and remote sensing.Meanwhile, optical sensor of photogrammetry keeping development in the direction of digital、wide array CCD、combining POS system and multi-digital cameras. So that, the new optical sensor puts many new problems and challenges forward the process of photogrammetry data. In the cameras calibration and image process, single digital camera system has been formed relatively perfect processing flow, with a lot of references and technical standards. On the contracy, using traditional method of calibtation and image process brings many problems in the multi-digital cameras system because of the relatively complicated process flow. In order to deduce the algithmn of calibration method and automatic mosaic of the airborne digital camera system, some important problems are deeply studied in this paper: 1. The significance of developing aerial remote sensing and airborne digital camera system in China was Analyzed; the constructive mode and the principle of geometric imagery according to some airborne digital camera systems at present was researched and summarized; the composition, working principle and aviation experiment of multi-digital cameras system were introduced; the importance of calibration in the airborne digital camera system and the problems of calibration and automatic mosaic was analayzed and summarized. 2. The reason of image motion and basic requirements of compensation was analyzed, and a new external backstepping type image motion compensation device based on the micro actuators was designed. By the experiment, the new device can effectively compensate image motion. Then, a great problem caused by backstepping type image motion compensation was analyzed. The problem is that the inner orientation elements of camera were changed in the moment of compensation. Therefore, the algrithomn was deduced in order to quantative analyzed the effect sizes to the precise of post-processing because of the changes of inner orientation elements and some solutions were given. 3. The difference of camera calibration between multi-digital cameras system and single digital camera system was researched and the process of calibration in the multi-digital cameras system was designed;indoor and outdoor 3D control field was build, the concept of System's Interior Orientation Parameters (SIOP) was put forward. Finally, the calibration method of interior orientation parameters、SIOP、distortion model、the correct parameters of exterior orientation parameters were researched. 4. A new multi-digital cameras system based on the concept of tilt-shift was detail analyzed, the Prototype Verification System was build and the estimation of this system was done in the indoor control field. In the calibration experiment, the difference between new system and traditional multi-digital systems wan analyzed and many problems brought by tilt-shift to calibration was solved in order to form new calibration process for the new systems.Finally, by the flight experiment, the paper improved that the new system can avoid many defect of traditional multi-digital cameras system, and can effective express the advantage of multi-digital cameras system. 5. The key technology of automatic mosaic among single group images of multi-digital cameras system and the SIFT algorithnm、image transformation based on the SIOP was researched. Meanwhile, on the basis of improving RANSAC, a modified method of eliminating error match points and optimizing transformation model for distorted images mosaic was researched. Finally, Through studying linear correction method of RRN, the paper put forward a new and high automatic RRN method based on Scale-invariant feature transform(SIFT) After emphatically analyzing and researching for the key technologiesof calibration and automatic mosaic of Airborne Digital Camera System, the emphatically research of image motion compensation and the process of calibration for multi-digital cameras system was build;The analyse and calibration process of multi-digital cameras system based on the concept of tilt-shif was improved; Automatic mosaic algrithnm among the single group images of multi-digital cameras system was improved. This paper can accelerate the improving of airborne digital camera system, especially multi-digital cameras system in the photography and remote sensing field.
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