Research On Large Scene Terrain Height Map Synthesizing Based On Single Sample

Terrain synthesis has always been a hotspot and difficulty in the field of computer graphics and images.The large scene simulated by computer is able to be used in the fields of three-dimensional games,battlefield environment,special effects of film and television,etc.Current terrain synthesis involves a lot of computation,which is difficult for users to control directly,and the synthetic terrain is not realistic enough.In order to provide users with a concise and creative way of terrain synthesis,in this paper,we mainly study the synthesis technology of large scene height map based on single sample.An interactive software system for terrain altitude map synthesis is designed and implemented finally.The main research results and innovations are as follows:(1)Aiming at the skeleton extraction of sample terrain maps,a skeleton extraction method based on profile recognition and minimum spanning tree is researched and implemented.Scanning terrain maps,sampling points are obtained according to sampling intervals,and a weighted undirected graph are constructed by connecting adjacent sampling points.Minimum spanning tree method is used to disassemble undirected graph to generate the prototype of terrain skeleton,and pruning operation is carried out to delete redundant branches and leaves of terrain skeleton to simplify the skeleton.Smoothing the feature points of the skeleton to obtain the terrain skeleton;(2)Aiming at the ridge line extraction problem of two-dimensional gray-scale terrain map,a ridge line extraction method based on flood-fill is proposed and implemented.A mask image is constructed to simulate the process of flooding,and the foreground contour is drawn in the mask image as the demarcation line between the flood and the mountain.Using flood-fill to contract the foreground contour of the mask image,the points of contour intersection in the mask image are marked according to the condition of water surface intersection.After the contour is contracted,ridge lines are extracted;(3)Aiming at skeleton extraction and skeleton feature graph construction of user sketch,a skeleton feature graph construction method based on flood-fill is proposed and implemented.The image is abstracted as a terrain model,and the ridge line extraction method based on flooding filling method is used to extract the skeleton and get the skeleton point set.The feature nodes are constructed according to the skeleton point set and the feature edges are constructed according to the search path of the feature nodes.Finally,skeleton feature graph of user sketch is obtained;(4)Aiming at the problem of synthesizing terrain height maps based on single sample that meet user's sketch expectations,a method of terrain height map synthesis based on image patch matching cost function is proposed and implemented.According to terrain skeleton and sketch skeleton,image patches with skeleton and without skeleton are constructed.The cost function of image patch matching is constructed,and the sample image patch with the lowest matching cost is selected for each sketch image patch and drawn to the corresponding position in the synthetic height map.Finally,a large-scale terrain height map based on a single sample and in line with user sketch expectations is synthesized.(5)Design and implement a large scene terrain height map synthesis system based on single sample.In order to verify the feasibility and validity of this method,through detailed requirement investigation,the functional modules of image display,skeleton extraction,topographic height map synthesis and terrain rendering are realized.The actual operation of the system is stable and the effect is good.