Demons算法是一种基于灰度信息的全自动非刚性配准方法，其配准结果容易受图像之间灰度不一致的影响，且迭代收敛速度较慢。针对这两个问题，提出了一种基于多项式最小二乘拟合的灰度归一化方法对灰度进行匹配，并在迭代过程中自适应调整浮动图像所受作用力以加快收敛速度。用改进后的算法与原算法及其他改进算法分别对乳腺X线摄片进行配准实验，对比结果表明，本文的改进方法能够更快地产生更精确的配准结果，配准后的图像增强了乳腺组织的真实变化，有利于乳腺癌的早期诊断。

Demons algorithm is an intensity-based fully automatic deformable image registration method.Its result is liable to be affected by the inconsistency of the intensity between the images，and its iterative convergence process is relatively slow.In this paper，a novel pretreatment approach of intensity normalization based on polynomial least squares fitting has been implemented to match the intensity between the images，and an accelerating algorithm for adaptively adjusting the deformation force of the floating image during the iterative process has been designed to speed up the process of convergence.This improved algorithm，the original algorithm and other improved algorithms have been applied to mammogram registration，and the results of the comparison show that the new method can obtain more accurate results with faster speed.The registered image which enhances genuine alterations in breast tissue would benefit the early detection of breast cancer.