关键词: 大规模地形, 快速离散余弦变换, 嵌入式零树编码, 数据压缩

Abstract:

The transmission, storage and processing of large-scale terrain data limit the real-time rendering speed of terrain, this paper presents an algorithm based on fast layered Discrete Cosine Transform（DCT） embedded zerotree coding to achieve terrain data compression, and then completes terrain rendering with view-based dynamic Levels of Detail（LOD）. Firstly, the fast DCT is used to replace the traditional DCT to transform the terrain data, and the different frequency sub-bands are reconstructed according to the spatial position, the low frequency is used as the input of the lower layer after the inverse DCT, repeat the above steps until the requirements are met. Then zero-tree coding is applied to the obtained multi-resolution frequency band. Finally, the terrain is re-rendered with dynamic LOD. The experiments show that the algorithm is relatively simple, compression rate and frame rate are improved effectively, which is more in line with human visual perception.

Key words: large terrain, fast DCT（Discrete Cosine Transform）, embedded zerotree coding, data compression