基于改进光线投射算法的体数据显示

光线投射算法属于直接体绘制（DVR）中应用比较广泛的算法，其优点是绘制质量高，但是存在采样点计算量大，绘制速度慢的问题.针对这一问题，本文利用投射光线在物空间的传递性质，提出了一种改进的计算采样点位置的算法，加快采样点的获取速度，提高图像三维重建的效率.该算法在PC机平台上得到了实现，不仅在图像质量上得到保证而且绘制速度又有很大提高，为图像的三维重建提供了有效的手段.

Volume Rendering Based on the Improved Accelerate Ray Casting Algorithm

The ray casting is a widely used basic volume rendering algorithm. It can get high quality image but the computation of traditional sampling-points method is overlarge and the rendering speed is very slow. Aimed at the shortcoming, an algorithm that takes the advantage of the recurrence relation of parallel projection line during the sampling process is presented to improve the speed of obtaining the sampling-points and the speed of reconstruction. Finally, the algorithm is realized on PC platform. The result shows that compared with standard ray casting algorithm, the accelerate algorithm does not only improve the rendering speed for nearly ten times but it does not reduce any image quality. It gives a more capable method for the application of medical image 3D reconstruction.