Study On Close-range Photogrammetry Point Cloud Acquisition Combined With Aerial Triangulation And SFM

With the accelerating process of digital city of China, point cloud acquisition of objects on the ground has become the important content of surveying and mapping work. Common Laser Scanning is high cost, inefficiency, difficult to processing data, and can not meet the requirement of point cloud quick acquisition. Therefore, this paper put forward a low cost and high efficiency point cloud acquisition scheme combined closerange photogrammetry data acquisition, aerial triangulation data processing in aerial photogrammetry and point cloud build with image in computer vision which based on Structure From Motion(SFM). Experiments have been designed to verify the feasibility of this scheme. The details are as follows:(1)Study on main theories and key technologies of image point cloud bulid in computer vision, and develop a potin cloud build sysem based on SIFT feature extraction and matching, Structure From Motion(SFM) and Patch-based Multi-View Stereo(PMVS), and testthe system with digital camera images to build point cloud. The result shows that this system has low requirement for the attitude of image, good integrity and build point cloud quickly. It can be a point cloud obtaining additional mean for local complex area in close-range photogrammetry(2)Aim at the requirement of data processing by aerial triangulation in aerial photogrammetry, preprocess the close-range photogrammetry data with image distortion correction, coordinate convertion and exterior orientation elements calculation. Then, analyse the accuracy and build point cloud. The result shows that the method can process with strip images, and it has low requirement for the overlap between two adjacent images and high precision. It also reduce the dependence of control points and can optimize the process of close-range photogrammetry data acquisition and processing on some degree.(3)Aim at the hollow in aireal triangulation point cloud, design a scheme of point cloud acquisition combined with aerial triangulation and SFM. Research on technologies of camera calibration, images acquisition and point cloud fusion. And design experiment to obtain point cloud of object. The result shows that the scheme has the advantage of low cost, high efficiency and dexterity, and can generate high precision full point cloud data by fill the hollow in aireal triangulation point cloud with SFM point cloud.