The author uses window width and level transformation to classify the volume data in Ray_casting method, compared to the traditional classification (classified by the sampled threshold), it enlarges the color difference between different tissue.

• 本文将医学中的窗位窗宽变换用于光线投射法的数据分类,这种分类方法比通常用的阈值分类更能清楚的反映不同组织的状态,通过不同窗位窗宽值可以清楚的显示比如脑中的肿瘤或是颅骨的被破坏的痕迹。