图像分割是图像理论发展的瓶颈， 过渡区是指图像中介于目标和背景之间的 特殊区域，借助于过渡区的确定进行图像 分割。主要介绍了过渡区提取的两大类方法 ：基于梯度的方法和基于非梯度的方法， 并对提取效果以及存在的问题做了简要分析。

Image segmentation is treated as a key issue in image processing and machine vision,  and has been the bottleneck of development.  Transition region is a special region located between the object and background.  Having the aid of extraction of transition region to segment image is a kind of burgeoning technology.  Two kinds of methods have been introduced: methods based on gradient and methods based on non-gradient.  Briefly,  the extracted effects and existent problem have been analyzed.