Estimating Rigid Transformation Between Two Range Maps Using Expectation   Maximization Algorithm
  We address the problem of estimating a rigid transformation between two point sets, which is a key module for target tracking system using Light Detection And Ranging (LiDAR). A fast implementation of Expectation-maximization (EM) algorithm is presented whose complexity is O(N) with $N$ the number of scan points. 
Shuqing Zeng
cs.RO