Application Of Tilt Photogrammetry In Urban 3D Single Model Construction

With the gradual rise of "Digital City", the construction technology of the 3D model of the data carrier is also developing rapidly. After years of exploration in many technology, Photogrammetry technology come to the fore, it can access large area efficiently so that rapid made 3D city model can come true,but the traditional Photogrammetry technology can only obtain ortho image data, lack of side information,based on this issue,gradually developed a new technology, namely Tilt Photogrammetry technology, the technology can obtain ortho image, also be able to get the side grain, provides a new idea for 3D city modeling. Tilt Photogrammetry technology is currently developing a new technique used in the construction of urban 3D model. It is different to conventional photogrammetry technology, using one ortho lens, four strabismus lens to obtain aerial images, to obtain positive photographic image at the same time also be able to get the true side texture information, which can be more efficient to build the three-dimensional model of a city. This paper combined with the Kunming urban built-up area of 430 square kilometers of the scope of use of tilt photogrammetry technology establishment of 3D city model,research the Tilt Photogrammetry systematically,analyze its important characteristics and key technology,and make the corresponding classified and summarized.The main contents are as following:(1) Through analysis and research in tilt image,summed up the ten basic characteristics of tilt image.And emphasis to using the geometric relations to analysis the resolution of the tilt image,and corresponding mathematical relationships is derived.(2) Introduce the image pre-processing technology, SIFT feature extraction methods, and from the feature matching technology to expand to the multi-view image matching technology and analysis and research.(3) Presents point cloud and pre-processing technology,analysis the main steps of model constructed and the need of constraint conditions. Finally,analysis and research in three key technology of the texture:the texture of automatic optimization,correct and texture mapping. Introduce the extraction and application of 3D city monomer model,and has carried on the corresponding analysis on basic theory of measured technology of 3D monomer model.(4) Combined with specific projects to analyze and research the theory and practice,corresponding to the whole technical process and technology theory, and the discovery and analysis of the existing problems,and summarizes the main source of problem are shade and ground instability and other reasons.