【作者】 钦桂勤；

【导师】 张永生；

【作者基本信息】 解放军信息工程大学 ， 测绘科学与技术， 2011， 博士

【摘要】 论文根据星载天线失重形变精密测量的迫切需求,利用水的浮力抵消部分重力原理进行地面失重环境的模拟,引入水下摄影测量技术。主要围绕水下近景摄影测量所涉及的理论和技术问题展开研究与试验,并结合星载天线型面的水下精密摄影测量进行了完整的技术验证。论文的主要工作和创新点如下:1.分析了光学系统中三对基点和基面构成的光学系统基本模型,得出摄影光学系统成像性能主要取决于基点和基面位置的结论;阐述了摄影光学系统与物方和像方所处介质折射率的关系。2.以过节点光线所描述的物像关系为基础,利用针孔成像原理诠释了单介质摄影测量“三点共线”理论,分析了单介质摄影测量的物像位置关系和主距大小。3.分析了相机镜头前为非空气介质时双介质摄影成像基点位置变化和投影中心位置改变的规律,提出了双介质摄影测量的“三点共线”理论;推导了“水下摄影系统主距近似为同一相机在空气中主距与所在水的折射率乘积”的关系,并通过试验验证了水下摄影测量“三点共线”理论和主距变化关系的正确性。4.分析了光在水中传播的特性及其对成像的影响,提出一整套方法和措施保证水下摄影成像质量,并为浅水中摄影测量作业设计、制作了水下摄影相机防护箱,成功应用于水下像片的拍摄。5.分析了相机水下摄影时内部参数标定的常用方法和特点,提出了水下相机标定的优化方案,并通过试验验证了该方案的有效性。6.分析了水下摄影测量误差主要来源,研究了水下成像系统尤其是相机防护箱对测量精度的影响,以及水下摄影环境与摄影测量网形对测量精度的影响。针对影响精度的关键因素进行了三类测试试验,结果表明摄影测量网形对精度影响较大,相机加防护箱的测量精度在水上和水下基本一致。7.提出将星载天线置于水中模拟太空失重环境进行型面变形测量方案,设计了针对1.3m口径柔性自回弹天线型面水下摄影测量的技术方案,成功地进行了水下摄影测量试验。试验结果表明,该天线置于水中所受浮力抵消了一部分重力,天线在水中与在空气中相比存在一定的变形。更多还原

【Abstract】 With the exigent requirement for precision measurement of the satellite antenna surface, the technology of underwater photogrammetry was introduced with the zero-gravity conditions. The simulated zero-gravity conditions were achieved with the gravity compensation by the flotage of water. Serial theory researches and technical tests were done on the close range underwater photogrammetry. The theory and technology for underwater photogrammetry were validated through the surface measurement of satellite antenna in water.Primary coverage of this dissertation and innovation were as following:1. The geometry model was analyzed and discussed among three couples of datum marks and planes in one optical system. The optical imaging system mainly depended on its datum marks and planes. The conclusion had been verified that the camera lens system depended on not only its structure but also the refractive indexes of object space and image space.2. The collinearity theory with three points was interpreted with the optical rays through the nodal points for one-media photogrammetry. The relation of position were analyzed among object, image and the principal distance f 0 of camera in one-media photogrammetry.3.Based on the variable projection center and principal distance of camera, the collinearity theory with three points was advanced of underwater photogrammetry. The conclusion had been drawn that the principal distance of underwater camera was magnified with a factor of water refractive index by the one in air. All those were validated by one test of underwater photogrammetry.4.The characteristics of underwater rays transmission and the effects on imaging were analyzed. Some methods and steps were recommended to improve underwater imaging quality. An equipment was designed and manufactured in order to protect camera from watering in underwater photogrammetry shallowly. And the equipment was performed successfully to take underwater photos.5.The common methods of underwater camera calibration and its characteristics were analyzed. One optimal scheme of underwater camera calibration was put forward. Experiment results have shown that this scheme was effective and successful.6.The error factors of underwater close-rang photogrammetry were analyzed. The influence on measurement precision was discussed, including the equipment of protecting camera, underwater environment and measurement network. The practical ways were taken out to reduce the influence of these factors. Three types of precision measurement tests were carried out. The results have shown that measurement network was more prominent than the others for precision. And the measurement precision for camera with protection equipment was accordant between underwater and on-top water of photogrammetry.7.The technical scheme and the method were presented for the underwater surface measurement of a 1.3m caliber Spring-Back antenna. The experiment was implemented successfully. The experiment results have shown that the flotage of water could proportionally compensate the gravity and the antenna surface in water was slightly distorted comparing with that in air.更多还原