It is essential to generate multi-resolution Triangulated Irregular Network (TIN) models dynamically and efficiently in three-dimensional (3D) visualization, virtual reality, and geographic information systems (GIS), because the data that needs to be processed is multiple in scale and large in volume. This paper proposes a new method, which extends the edge collapse and vertex split algorithms, to dynamically generate a multi-resolution TIN models. In contrast to previous approaches, a new method is proposed to encode and store vertex dependency relationships in the multi-resolution model. As a result, the validity of vertex splits and edge collapses is improved; the efficiency of storing data is also enhanced by the proposed method. To evaluate the performance of the proposed method, we further extend the assessment to (a) time cost; (b) the quality of the multi-resolution TIN model; and (c) the view-dependent multi-resolution model. The root mean square error (RMSE) of the elevation of the vertex and the quality of the shape of the triangle are adopted to evaluate the quality of a generated multiresolution TIN model. The results of the experiment demonstrate that the proposed method performs better than previous methods in terms of time cost, and can achieve multiresolution TIN models with a higher accuracy.

空间数据获取与建模技术的飞速发展使高分辨率、高精度三维模型的快速生成成为现实，随之引起了一系列问题亟待解决，如：大数据量三维模型的快速可视化与快速网络传输。根据不同的需要对高分辨率的三维模型进行多分辨率描述是解决上述问题的一个有效途径。针对上述问题本文提出了一种快速、稳健的算法用于大数据量三维模型的多分辨率描述与网络传输。实验结果表明：该算法在运行效率、多分辨率模型的精度与解码以及三维模型的网络传输速度3个方面均取得了很好的效果。该研究结果为海量三维模型的快速可视化以及快速网络传输打下了的坚实的技术基础。

multi-resolution TIN model is an important issue in the contexts of visualization, virtual reality (VR), and geographic information systems (GIS). This paper proposes a new method for constructing multi-resolution TIN models with multiscale topographic features preservation. The proposed method is driven by a halfedge collapse operation in a greedy framework and employs a new quadric error metric to efficiently measure geometric errors. We define topographic features in a multi-scale manner using a center-surround operator on Gaussian-weighted mean curvatures. Experimental results demonstrate that the proposed method performs better than previous methods in terms of topographic features preservation, and is able to achieve multi-resolution TIN models with a higher accuracy.

提出一种用于网络环境下多分辨率传输矢量地图数据的算法，此算法采用“点删除”技术用于多分辨率描述原始的矢量地图数据，而且能够避免空间对象的自相交和维护拓扑关系的一致性。以此算法为基础开发了一个Client/Server结构的实验软件，在实验结果的基础上评估了该算法对提高网络环境下矢量地图数据传输效率的效果。实验结果表明该算法用于矢量地图数据的多分辨率快速传输是有效的。

Recent advances in 3D spatial data capture, such as high resolution satellite images and laser scanning as well as corresponding data proc-essing and modeling technologies, have led to the generation of large amounts of datasets on terrains, buildings, roads and other features. The rapid trans-mission and visualization of 3D models has become a ‘bottleneck’ of internet-based applications. This paper proposes a robust algorithm to generate multi-resolution models for rapid visualization and network transmission of 3D models. Experiments were undertaken to evaluate the performance of the proposed algorithm. Experimental results demon-strate that the proposed algorithm achieves good performance in terms of running speed, accuracy, encoding of multi-resolution models, and network transmission.