Research On Pretreatment And Three-Dimensional Reconstruction Of Dem Data

Digital elevation model (DEM) is a model of using the form ordered arrays to represent the ground elevation. It is widely used in many fields.In this paper, DEM pretreatment includes interpolation and simplification. DEM has a stable accuracy, there may not be enough number of control points in complex regions and there may be redundancy in the simple regions. So we should interpolate and simplify DEM in order to achieve completion voids and reduce the amount of data. Interpolation is mainly for some empty and not very good point set during data collection. Through a certain algorithm to generate a new point of DEM sequence according to the sequence near the point to be interpolated. Based on the different characteristics of DEM, respectively, we can get different effects on different DEM. The bilinear interpolation and fractal interpolation algorithm are used for data completion. We simplify the area with small undulating or small amount of information, so that the display can consume less memory and storage, and obtain a good display effect. Fractal is the essential characteristic of natural scenes. It can describe the irregular extent of surface topography. So it is used for digital terrain generation. We first applied fractal characteristics in simplified process of digital elevation model. We propose a new clustering simplification algorithm based on fractal characteristics of the digital elevation model, using the fractal dimension for data simplifying and merging in different subclasses. The experiments compared with classical algorithms show that this algorithm has the characteristics of precision, small voids and high terrain retention.For the three-dimensional reconstruction of DEM data, as the three-dimensional characteristics of DEM data, three-dimensional reconstruction meets the human visual habits. This paper uses greedy projection triangulation algorithm for DEM three-dimensional reconstruction. The reconstructed triangular meshes meet the Delaunay criteria, with good visual effect.Evaluation of the DEM data after reconstruction, its quality needs to be evaluated since above operation, in order to test the effectiveness of the algorithm. In this paper, the classical algorithm in IQA is applied to the field of DEM quality assessment, the method took the three-dimensional characteristics of the human visual system HVS and DEM data into account, and also image quality assessment algorithm. Multi-angle DEM data quality assessment compares with classical algorithms of the areas to prove the effectiveness and practicality of the algorithm.