The Development Of Texture Synthesis Approach For Three-dimensional Vector Terrain Model

With the rapid development of Digital Earth,film,animation and the game industry,the research and application of geographic information is becoming increasingly important in various fields,especially the drawing and rendering technology for realistic graphics faces increasing challenges.Traditional terrain rendering technique commonly use hierarchical tinting method or roughly render the terrain with single feature texture image.First,the hierarchical tinting method can well describe the outline of the terrain features,but it does not reflect any surface features;and the rendering result of single feature texture mapping method always could not meet the realistic feature of terrain surface for it not taking the elevation and the actual geographical features into account.In consideration of the weakness of traditional hierarchical tinting method and the texture mapping method,we present a realistic terrain rendering method which combines the multi-figures texture synthesis and the terrain parameterization.(1)Aiming at complex terrain textures,we improved the original texture synthesis algorithm.First,in order to improve the synthesis effects for terrain texture,we add the matching of texture structures to the pixel-based matching method,and the texture structures of the terrain texture is obtained by the Canny edge detection algorithm;Second,in order to speed the matching for texture structures during the texture synthesis process,we present using Chamfer Matching algorithm to speed up the process of texture structures matching;Third,in order to synthesize multi-features terrain textures,we propose to control the multi-figures texture synthesis through control mask image which generated by the elevation values of the original terrain.Finally,after the processing the above steps,we can get the final multi-features images of terrain texture;(2)In order to reduce the texture mapping distortion and deformation problems,we parameterize the three-dimensional terrain grid firstly,and then use Mip-map technique to anti-aliasing during the sampling of the texture mapping.In addition,all of the terrain data used during the experiment is based on real DEM data,and the experimental results indicate that the terrain rendering effects by our method is superior to the traditional terrain rendering method.