The Generation And Compression Research Of Stable Progressive Meshes

With the improvement of the mobile Internet and the popularity of intelligent mobile terminals,Mobile 3D graphics application becomes more and more widely used.However,the 3D graphics development applications of mobile devices are hindered by limited and unstable bandwidth of mobile network,low processing capacity and low power consumption of mobile devices.According to features of 3d mobile applications,this thesis focuses on the generation and compression method for progressive mesh,and optimizations the existing algorithm.Our aim is to improve the compression ratio and reconstruct speed for 3D graphics under the condition of ensuring the visual effect.The main contributions of this paper includes:1.Due to the low reconstruct speed caused by offset vector pair processing,a stable structure for progressive mesh,named stable progressive mesh,is proposed.The base mesh is reorganized by half-edge structure.Then the offset vector set is reordered in accordance with edge sequence in the base mesh layer by layer.And the stable progressive mesh is achieved.2.Aiming at the problem of the low speed of traditional embedded zero-tree coding,progressive mesh tree is established based on stable progressive mesh.A new method to construct the offset wavelet tree is designed,which avoids to the process of constructing the quad-trees' in traditional embedded zero-tree coding.3.Since there may be a possibility that the length of some offset vectors are longer than the normal,the offset vectors of many models are statistically analyzed.And the setting strategy for initial threshold ?0 of traditional embedded zero-tree coding is modified,which improves the compression ratio and the visual effects of the reconstructed model.A simulation system is developed for the construction and test the above algorithms.Experiment shows that the storage of stable progressive mesh is less than that of the traditional progressive mesh 2/3.Both the reconstruction speed and the compression ratio decrease with the increasing of model data size.When the mesh data size increases to above 10 MB,the speed of compression reconstruction of the stable method is faster 100 times than traditional one.