| The dissertation makes a presentation of the research and realization of the 3-D digital terrain map. This project is made to meet the development of the battlefield armored reconnaissance tank system and its training-simulation system. The main content of this dissertation includes the processing of the distillation of the contour line from the paper map and the design of the B-spline surface interpolation for the scattered data. In addition we also introduce the realized step of the display of the three-dimensional terrain map.First in chapter 1, we introduce the background of the 3-D digital terrain map, discuss the resolution of the data source of the 3-D digital map and propose an idea that retrieving 3-D data with B-spline surface interpolation based on the contour line distilled from paper map.In the chapter 2, the basic algorithm of image processing methods are introduced here. We discuss the realization of distillation contour line from the scan image of the paper map and propose the Multi-Dimensional Thresholding(MDT) to deal with the color image segmentation. In addition, we also introduce software design to evaluate the contour line.In the chapter 3, we introduce the theory of the B-spline. We compare the B-spline curve interpolation and B-spline surface interpolation, analyze the fault of the B-spline curve interpolation and point out that we should use B-spline surface interpolation instead of B-spline curve to keep the continuity of the data result. Also, we introduce the way to get control point from value point. Then we propose the multi-step fitting of the dense and scattered data to construct B-spline surface , this algorithm perfectly resolve the obstacle of denseness and scattering of the contour line data.In the last chapter, we introduce the OPGEGL methods to realize the 3-D display on the computer and the software design process and the realization detail. With OPENGL, we can display the 3-D digital terrain map dynamically and reelingly. |
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