In this paper, we first introduce the concept of the depth of field (DOF) in machine vision systems, which serves as a
basic building block for our study. Then, related work on the generalization of the fundamental methods and current
status with regard to extending the DOF is presented, followed by a detailed analysis of the principles and performances
of some representative extended depth-of-field (EDOF) technologies. Finally, we make some predictions about the
prospects of EDOF technologies.