【作者】 赵颖； 周芳芳； 樊晓平；

【Author】 Zhao Ying,Zhou Fang fang,Fan Xiao ping Research Center for Automation Engineering,Central South University,Changsha 410075 Hunan,P.R.China

【机构】 中南大学信息科学与工程学院自动化工程研究中心；

【摘要】 在体绘制中传递函数将体数据转换成颜色、不透明度等光学属性,决定了绘制的效果,成为体绘制研究的关键。本论文提出了基于边界面设计高斯型传递函数的高效方法。该方法首先通过梯度阈值提取边界体元,简化数据场,然后将提取边界面的目标函数设计为计算边界面的平均梯度的极值。最后利用提取出的边界面来设计高斯型传递函数,并采用分段分析积分法实现了采样点的颜色合成。该设计方法在保证绘制效果的同时,提高了边界面的准确度和传递函数的设计效率。更多还原

【Abstract】 In direct volume rendering,transfer functions map data points to optical properties such as color and opacity.This paper advances the use of boundary information in transfer functions with a methodology for computing high-quality bound-ary measurements.An efficient approach for the extraction of boundary from volume datasets was describes.First,boundary voxels are defined by gradient magnitude threshold to refine the dataset.And then an objective function to detect the good boundary can be defined as the surface integral of the mean gradient magnitude.The boundaries are detected as maxima in cumulative Laplacian-weighted gray value histograms divided by boundary area values,with a computationally efficient method that requires only a single pass through the boundary volume.Last,a Gaussian transfer function is designed by the boundaries for high-quality rendering,and the transfer function can be analytically integrated over a line segment under the assumption that data values vary linearly between two sampled points.Analytically integrated segment can then be composed using standard techniques.更多还原