在统计计算中，最大期望（EM）算法是在概率模型中寻找参数最大似然估计或者最大后验估计的算法，其中概率模型依赖于无法观测的隐性变量。最大期望算法经常用在机器学习和计算机视觉的数据聚类（Data Clustering）领域。(In statistical computation, the maximum expectation (EM) algorithm is an algorithm to find the maximum likelihood estimation or the maximum posteriori estimation of parameters in the probability model, in which the probability model depends on the hidden variables that cannot be observed. Maximum expectation algorithm is often used in the field of machine learning and computer vision data clustering.)