Abstract: For the limitation of existing hardware and technical conditions，space between virtual object and fingers often emerges after grasping recognition，which may be perceived by user if they haven’t been occluded.Changing the position of virtual object immediately to eliminate penetration and space may result in virtual object jumping obviously.Firstly，the occlusion relation between virtual object and hand is analyzed，and the judgment of it is realized by 3D graphics’ theory.Secondly，the grey theory is applied to predict the hand’s movement with this judgment.Lastly，according to the prediction’s result and the principle of max speed difference，the virtual object’s velocity can be adjusted adaptively.The results show that by using this method，the grasp success rate can be increased greatly，and virtual object and hand can conflate naturally.

Key words: grasp, occlusion, grey theory, max speed difference, augmented reality

摘要： 由于现有硬件和检测条件的限制，抓取中手指与虚拟物体之间往往会有穿透和空隙现象出现，无遮挡时就会被用户察觉;如果立即改变虚拟物体的位置来消除穿透和空隙，会使虚拟物体产生明显跳跃，缺乏交互真实感。分析了运动时手指与虚拟物体的遮挡关系，运用三维图形学中的理论实现对不遮挡情况的判断;将其与灰色预测理论相结合，实现对手的移动预测;根据预测结果和最大速度差原则，自适应地调整虚拟物体的速度，使虚拟物体与手逐渐融合。实验结果表明，使用提出的方法，既可提高抓取的成功率，又能保证虚拟物体与手的自然融合。

关键词: 抓取, 遮挡, 灰色理论, 最大速度差, 增强现实