Study On Algorithms For Reconstructing 3-D Surface From Terrain Contours

With the development of the technology of underwater laser and Visualization in Scientific Computing,the technology of the seabed physiognomy rendering growns up increasingly. The distance-choice underwater laser system adopting green-blue laser takes on the performance of the better resolution and effective distance,through it we can explore seabed, and obtain a series of multi-distance images,with these images we can rendering the seabed physiognomy. The studies of this dissertation are supported by the Natural Science Foundation of China under grant number 60272099 "New method to 3-D imaging with underwater laser realizable". The contents of studied in this dissertation is how to reconstruct the 3-D seabed physiognomy with a serial of the seabed terrain contours, it mainly contain the acquirement of the seabed terrain contours, interpolation between the contour images, 3-D surface reconstruction, data compression, these work mainly include:1. Introducing the principle of the distance-choice underwater laser system, basing the property of distance-choice and the characteristic of the seabed physiognomy, we simulate the multi-distance images with the DEM image.2. Contour interpolation. The serial contours's resolution in Z direction is less than the resolution in X and Y direction, the shape of the adjacent multi-distance underwater contour images vary observably, so the key technology of reconstruction is interpolation. With interpolation between the adjacent contours, a contour can change naturally to another adjacent contour. Several interpolation methods are discussed and compared, and Fourier description is introduced as a interpolations. Basing on the idea of wavelet multiresolution analysis, a new interpolation method is presented, decomposing the contour under multi- scale, and interpolate the contour under multi-scale.3.Contour compression. With the interpolation between contours, the contours's resolution in Z direction is close to the resolution in X and Y direction. The datum of contour become tremendous as meeting to the demand of 3-D surface recontruction, so the data compression is inevitably. We study the fractal characteristic of the terrain contour, and compress the datum greatly utilizing IFS to describe the the terrain contour.4.Last, we discuss several methods of 3-D surface recontructon, considering the practical instance, adopt the Marching Cubes to recontruct the terrain surface.