含义：

• IterativeClosestPointNonLinear is an ICP variant that uses Levenberg-Marquardt optimization backend.

The resultant transformation is optimized as a quaternion.

The algorithm has several termination criteria:（终止条件）

1. Number of iterations has reached the maximum user imposed number of iterations (via setMaximumIterations)
2. The epsilon (difference) between the previous transformation and the current estimated transformation is smaller than an user imposed value (via setTransformationEpsilon)
3. The sum of Euclidean squared errors is smaller than a user defined threshold (via setEuclideanFitnessEpsilon)
   
   来源： http://docs.pointclouds.org/trunk/classpcl_1_1_iterative_closest_point_non_linear.html#details

• ICP优化步骤，既可以用于局部几何特征不变描述算子中也可以用于全局几何特征不变描述算子。

文献：

用法：

ICP（IterativeClosestPoint）

原文：http://www.cnblogs.com/jack-wangchong/p/6538098.html