中文摘要：

摘要为了帮助医生对医学图像进行准确的定位和诊断,在显示感兴趣区域的同时保留其上下文信息,提出一种保留上下文环境体绘制方法.首先记录沿光线方向的首个等值面的空间位置;然后根据采样点到等值面的距离和采样点处的梯度构造衰减函数,将衰减函数作用于不透明度转换函数,以控制光线合成.对头、腹和脚部等CT数据的实验结果表明,该方法可以在保留组织轮廓清晰的前提下增强感兴趣区域显示.

英文摘要：

A context-preserving volume rendering approach is proposed for accurate medical image visualization and analysis,to enhance the display of region of interest（ROI） and preserve the clear shape cues of background.By the approach,a specific iso-surface along the viewing ray is first located,and secondly for any sampling point,its gradient and its distance to the iso-surface are calculated.Then,an attenuation function is constructed using the distance and the gradient of the sampling point.Finally,the attenuation function is integrated into opacity transfer function to control the rendering.The proposed method is tested on the head,abdomen,and feet CT data of digital human.The experimental results show that the display of ROI is efficiently enhanced while the contours of the tissue are well preserved.