地面影像三维重建技术研究
文献类型：学位论文
| 作者 | 池梦群 |
| 学位类别 | 硕士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院大学 |
| 授予地点 | 北京 |
| 导师 | 陈曦 |
| 关键词 | 地面近景影像，相机检校，拍摄方案，影像匹配 |
| 学位专业 | 工程硕士 |
| 中文摘要 | 城市三维重建方法的研究和应用已经比较广泛，早期建模的AutoCAD、3dMax等软件根据场景进行模仿构建，这些类似的软件在城市大范围三维重建中效率低下，效果不真实。利用无人机技术搭载摄影相机、激光扫描仪等传感器得到的数据获取效率高，并且可根据不同分辨率的影像可以达到不同的细节水平，广泛用于大范围城市三维模型的快速重建，但是仍然存在精度与遮挡问题。近景摄影测量也是三维重建的重要途径，与单纯利用无人机航拍下视影像及倾斜影像进行建模相比，在城市三维重建中引入地面近景摄影影像，可以提高模型的精度。首先，由于其拍摄是在近地面进行街景影像采集，采集距离近，分辨率高，信息丰富。其次，地面近景采集的影像光轴方向与航拍的摄影光轴之间的夹角大于90°，甚至接近180°，弥补了航拍影像拍摄方向的局限性，使得地物角度信息更丰富，为构建完美的真三维模型提供了可能性。地面影像应用于三维建模首先要解决数据的获取与融合问题，基于此本文对地面近景影像的获取与处理技术展开研究，主要研究成果如下：（1）完成实验所用相机的检校及效果分析。论文设计了检校影像拍摄方法，获取了检校影像；基于检校影像对实验用数码相机进行检校，得到其畸变参数，检验结果中误差达到0.0018mm以下，精度较高；为验证检校结果稳定性研究提出了两种验证方法进行实验验证，结果表明相机检校成功。（2）完成影像拍摄方案的设计。本论文根据测区的状况及成图要求对航拍影像采集方案和地面近景影像的采集方案进行设计。航拍影像采集方案主要包括飞行区域确定、航线设计、重叠度确定等；地面近景影像的采集方案主要设计以下几种方法：平行多基线正直摄影、平行多基线密集正直摄影、旋转多基线交向摄影、回转多基线正直摄影；还设计了基于旋翼飞行器的垂直方向摄影方案。（3）完成地面拍摄方案的可行性验证与评价。为验证本文的地面影像采集方案的可行性，首先对地面影像进行影像空三加密与建模，并设计了相对定向评价方式，对其模型精度进行评价与验证。实验结果的数据表明几种摄影方案的模型精度都在8cm以下，总结几种方法的误差大小得出，基于控制点的平行多基线正直摄影方式为最优地面摄影方案。（4）进行了航拍影像与地面影像联合解算实验。本论文通过影像匹配与点云匹配两种方式来进行实验。对SURF-RANSAC算法进行讨论并设计得到了影像匹配程序，基于此程序进行多组影像匹配实验，实验表明，同源数据匹配效果良好，航拍影像和地面影像这两种异源数据由于拍摄视角与图幅差距匹配效果不明显，不同分辨率影像匹配效果良好；基于点云匹配算法通过多次实验与设计对两个数据源生成的点云数据进行匹配实验，最终得到二者的联合后的点云数据，为后续进一步工作提供参考意义。 |
| 英文摘要 | The study on 3D reconstruction technique is a hot subject and a variety of 3D city modelling methods have been increasingly applied in a growing number of fields. Many early used 3D modelling softwares, such as early used AutoCAD, 3DMax, accomplish 3D reconstruction according to the real scene. These methods can only show low levels of detail contour features of urban landscape. Using actual image textures and point cloud data obtained by aero-photogrammetry system and airborne radar system to accomplish 3D reconstruction is rising. Because the efficiency of using sensors (i.e. photographic camera and laser scanner) carrying on unmanned aerial vehicle to obtain images is very high and different precisions can be achieved based on different resolution images, the images acquired by unmanned aerial vehicle technology are widely used in large-scale 3D city building reconstruction. Close-range-photogrammetry is another important methods that is used in 3D reconstruction technique. Compared to images obtained by unmanned aerial vehicle technology, close-range photogrammetry can improve the precisions of 3D modelling based on following two characteristics: first, because close-range photogrammetry can obtain ground images at a much closer distance, the ground images have higher resolutions and more information; second, because the inclined angle of camera axis between ground images obtained by close-range photogrammetry and images acquired by unmanned aerial vehicle exceeds 90°, which makes the angle information more abundant. To establish 3D model with higher precision, the thesis focuses on the modeling methods of ground close range images. The main novel contributions in this project are described in the following: (1) Camera calibration and precision analysis were finished. This work came up with some methods for camera calibration, and the calibration results were analyzed. We calibrated variable parameters of our camera with RMSE of 0.0018mm. Two methods were used to validate the stability of calibrations and results shown that the camera calibration is reliable. (2) The design of photography plan was proper. This work made several aerial and ground photography plans according to the conditions of the observation regions and the requirements of mapping. Aerial images capture method mainly includes the flight area determination, course design, overlapping degrees determine, etc. Ground close shot images acquisition methods are described as: parallel multi-baseline integrity more photography, parallel multi-baseline high-density integrity photography, rotating multi-baseline photography. Furthermore, a photography solution was presented based on the vertical direction of the rotor aircraft. (3) Validation and evaluation of ground images photographic approaches. In order to verify the feasibility of ground images photographic approaches, the ground images were modelled and then the absolute orientation and relative orientation were combined to validate and evaluate the precision of proposed models The validation results shown that the precision of all photographic approaches below 8cm, and normal case photography based on reference points is the best photographic approach (4) Calculation experiment for the combination of aerial images and ground images was finished. Image matching and point cloud matching were implemented in this thesis. The image matching program was proposed based on the SURF - RANSAC algorithm and then the matching experiments were conducted according to the proposed program. The results shown that the best matching effect is obtained by the same source data. And then we took several experiments to match the point cloud data of the two sorts of data, and finally we got the nested result. |
| 学科主题 | 测绘工程 |
| 语种 | 中文 |
| 源URL | [http://ir.xjlas.org/handle/365004/14954]  |
| 专题 | 新疆生态与地理研究所_研究系统_荒漠环境研究室 |
| 作者单位 | 中科院新疆生态与地理研究所 |
| 推荐引用方式 GB/T 7714 | 池梦群. 地面影像三维重建技术研究[D]. 北京. 中国科学院大学. 2015. |
入库方式： OAI收割
来源：新疆生态与地理研究所
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