Development of a 3D video-theodolite image based survey system
The scope of this thesis is to investigate and to develop a zoom lens videotheodolite system, which is formed by a zoom lens CCD camera, a motorised theodolite and a computer with the developed system software. A novel automatic calibration procedure is developed for the zoom lens CCD video-theodolite system. This method is suitable for the efficient calibration of any other video-theodolite system used in fieldwork. A novel image edge detection algorithm is developed. The maximum directional edge detection algorithm depends on the maximum directional gradient to judge the edges in an image. A novel line detection algorithm based on the Hough lines transform was developed for the applications of the video-theodolite system. This new algorithm can obtain not only the line parameters of r and 9 but also the data of the two terminal image points of the detected line. A novel method of constructing panoramic images from sequential images is developed based on the zoom lens video-theodolite system. It is effectively applied in the system to generate a panorama of a scene. A novel image matching algorithm is developed. The line features are matched with the constraint of epipolar lines. Through an experiment to match real world buildings, it is shown that the novel stereo matching algorithm is robust and effective. Another novel image matching algorithm is also developed. This algorithm is used to automatically measure the image displacement between the stereo images for the video-theodolite system. The accuracy of the zoom lens video-theodolite system is evaluated by three experiments. The measuring accuracy of this system can be within 0.09 pixels. The software of this system based on PC system is developed. It has a standard MFC windows interface with menu controls. This system software includes the control functions, measuring functions and image processing functions for the zoom lens video-theodolite system.