说明：  首先，我们将看看如何使用ConditionalRemoval滤波器，它可以一次删除满足对输入的点云设定的一个或多个条件指标的所有数据点。然后我们将学习如何使用RadiusOutlierRemoval滤波器，它可以删除在输入的点云一定范围内没有至少达到足够多近邻的所有数据点。
(First, we ll look at how to use ConditionalRemoval filter, it can delete all of the data points to meet a set of input point cloud or more conditions index. Then we will learn how to use RadiusOutlierRemoval filter, which can be removed within a certain range of the input point cloud does not reach at least all of the data points are enough neighbors.)