LATE水平集图像分割模型的矩形窄带法  

Rectangular Narrow-Band Method for Image Segmentation of LATE Level Set Model

作　　者：曾笑云 杨晟院[1] 潘园园 刘洋 左国才[2] ZENG Xiao-Yun;YANG Sheng-Yuan;PAN Yuan-Yuan;LIU Yang;ZUO Guo-Cai(College of Information Engineering,Xiangtan University,Xiangtan 411105,China;School of Software and Information Engineering,Hunan Software Vocational College,Xiangtan 411100,China)

机构地区：[1]湘潭大学信息工程学院,湘潭411105 [2]湖南软件职业学院软件与信息工程学院,湘潭411100

出　　处：《计算机系统应用》2019年第11期10-18,共9页Computer Systems & Applications

基　　金：国家自然科学基金(11571293)~~

摘　　要：窄带法是水平集图像分割的一种常见的加速方法.传统窄带仍然存在冗余的计算区域;传统窄带法与LATE (Local Approximation of Taylor Expansion)水平集模型结合时,图像分割效率反而可能下降.针对这些问题,本文提出了一种基于LATE水平集图像分割模型的矩形窄带法.在每次LATE水平集迭代之前,对水平集做如下窄带处理.首先找出水平集的所有过零点;然后对过零点做活动约束,剔除不活动的过零点,有效缩小窄带范围;再对活动约束的过零点生成矩形窄带;对重叠的矩形窄带进行合并优化,使得矩形窄带总面积尽可能小.最后,在矩形窄带范围内求解水平集微分方程,更新水平集,完成本次迭代.在水平集演化的不同阶段,对传统窄带法的窄带面积与本文矩形窄带面积进行了比较.随着迭代次数增加,矩形窄带面积与传统窄带法的窄带面积之比逐渐减小到0,说明矩形窄带法有效地减少了冗余计算量.针对不同程度的灰度不均匀图像,本文方法与LATE方法、结合LATE模型的直接窄带法、以及结合LATE模型的DTM窄带法进行了比较.直接窄带法和DTM窄带法的分割速度反而慢于LATE方法.对灰度严重不均匀的图像,直接窄带法和DTM窄带法的分割质量受到了较大影响.本文方法在保持较好分割效果的条件下,分割速度快于LATE方法.本文的矩形窄带方法有效地降低了算法复杂度,提高了图像分割效率.The narrow-band method is a common acceleration method for level set image segmentation. The traditional narrow-band still has redundant computational regions;When the traditional narrow-band method is combined with the LATE(Local Approximation of Taylor Expansion) level set model, the image segmentation efficiency may be reduced. In order to solve these problems, a rectangular narrow-band method based on LATE level set image segmentation model is proposed in this study. The level set is subjected to the following narrow-band processing before each LATE level set iteration. First, find out all the points of zero crossings of the level set;second constrict the points of zero crossings by the activity constraints, eliminate the inactive points of zero crossings, and effectively reduce the area of the narrow-band,then generate a rectangular narrow-band for the points of zero crossings by the active constraints, optimize the overlapping rectangular narrow-band so that the total area of the rectangular narrow-band is as small as possible. Finally,the level set differential equation is solved in the narrow-band of the rectangle, and the level set is updated to complete this iteration. In the different stages of the level set evolution, the area of the traditional narrow-band and the rectangular narrow-band of this study are compared. As the number of iterations increases, the ratio of the area of rectangular narrowband to the area of traditional narrow-band is gradually reduced to zero, indicating that the rectangular narrow-band method effectively reduces the amount of redundancy calculation. For images with different degrees of intensity inhomogeneity, the proposed method is compared with the LATE method, the direct narrow-band method, and the DTM narrow-band method. The direct narrow-band method and the DTM narrow-band method have lower segmentation efficiency than the LATE method, and the segmentation quality is greatly affected for some images with severe intensity inhomogeneity. Under the condition of maintaining

关 键 词：活动约束 矩形窄带 LATE水平集模型 灰度不均匀 图像分割 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]