基于小波的网络多分辨率体绘制

为了能在网络环境下，快速地进行三维绘制，提出了一种网络环境下的基于小波的体数据多分辨率体绘制方法，该方法采取基于客户端的三维重建方案，首先利用三维小波的多分辨率分析方法，将体数据分解为不同分辨率下的离散逼近信号与高频细节信号；然后按先离散逼近信号，后高频细节信号的次序将数据传输到客户端；最后在客户端实现由粗及精的、渐进式的三维绘制。在这个过程中，一种3D的Mallat滤波器组被用来加速体数据的3D小波分解与重构，一种离散的简略化小波域体绘制方程被用来满足体绘制的实时性。实验结果表明，由于该方法仅需要12．5％或更低的数据量，即可以绘制出品质良好的图像或图像的概貌，所以非常适宜于需要频繁选择、交互的三维图像网络系统。

Wavelet-based Multiresolution Volume Rendering in Network

A method of wavelet-based multiresolution volume rendering is presented for accelerating 3D reconstruction and interaction of volume data set in network. The scheme is adopted that the volume rendering takes place on client's workstation, in which volume data set on net server is first decomposed into the discrete approximation and detail coefficients by wavelet multi-resolution analyzing, and then these coefficients are orderly transmitted to client's workstation on which the low resolution image is first rendered by using approximation coefficients and successively refined by using detail coefficients as they are arriving. In this process a group of 3D Mallat filters is employed to speed up 3D wavelet decomposition and reconstruction of volume data set, and a discrete and predigested optical model for wavelet domain rendering is brought forward to satisfy real time request of volume rendering. The experiment results show that the method in this paper is highly propitious to the network for frequently selecting and interacting images, because high-quality images and/or outlines can be produced in 12.5 percent and/or much less of volume data set.