The Study On Modeling And Resolving In The Application Of Digital Close-range Photogrammetry To The Tunnel Project

So many tunnel projects are in process, but none can carry out without surveying. Especially when comes to the safety of the project, many researchers pay their attentions to the country rock deformation and the tunnel contour measuring. Recently, some studies in internal or international level are trying to apply the digital close-range photogrammetry methods into the tunnel project as to improve the efficiency and the precision. This paper follows their step and discusses the applying methods of non-metric digital camera in the tunnel project, in order to find out an economic, convenience and high-precision method.The methods to introduce digital close-range photogrammetry into tunnel project are expatiated and analyzed at the first place in this paper, which not only include using the direct linear transformation method to resolve the three dimension coordinate information of the points in two-image photogrammetry to acquire the country rock deformation and the tunnel contour information, but also bring out the manner and theory in country rock deformation, which compares the single picture in each period to collect the changes of the points in two dimensions. Furthermore, flux of light balancing method is used to resolve the series images to get high quality results.As to assist the calculation of the latter two methods, the content and methods to calibrate the camera are being studied in necessary. In order to calibrate the elements of interior orientation and the errors bring out by several distortions, we have to describe them quantificationally. The error models in the methods of test range calibration and self-calibration, which are being chosen as appropriate ways, were built up. Then, the matters need attention in the experiment are figure out and execute in the three dimension controlling field before we achieve the calibration result.After that, the models of the direct linear transformation method, single picture in each period comparison method and flux of light balancing method have been built up and resolved step by step. The matters need attention in the experiment are figure out and execute in the tunnel experiment, which helps to acquire the information. Then, we compared the results of the two methods since the target messages were processed.To sum up, the models and solutions of the three applying ways and two calibration methods mentioned before are achieved in this research. The results are not quiet well because of the distinguishability of the camera, but it can be improved to higher the precision in the future as well as applying the real-time calibration method.