【摘要】 直接体绘制本质是重采样与图像合成。其光线投射算法从屏幕上的每个像素点出发,沿设定视点方向,发出一条射线,沿该射线选择若干个等距采样点。求出该采样点的不透明度值及颜色值,从而计算出屏幕上该像素点处的颜色值。抛雪球算法则用足迹函数计算每一体素投影的影响范围,用高斯函数定义强度分布。最后计算出其对图像的总体贡献,并加以合成,形成最后的图像。更多还原

【Abstract】 The essential of direct volume-rendering technique are re-sample and image synthesize. Ray casting were stared out at every pixel on screen along viewpoint direction, and then some sample points were selected on the line. The RGB of the pixel were obtained to calculate opacity and RGB of every sample points. The footprint function was used by splatting to compute the effect range of every pixel, and then define intensity distributing by Gaussian function. At last, obtain ultimate image by synthesizing every pixel’s contributions.更多还原