西安电子科技大学学报 ›› 2016, Vol. 43 ›› Issue (3): 67-72.doi: 10.3969/j.issn.1001-2400.2016.03.012

• 研究论文 • 上一篇    下一篇

一种自适应的CT图像联合代数重建算法

乔全邦;黄力宇;贺志杰   

  1. (西安电子科技大学 生命科学技术学院,陕西 西安  710071)
  • 收稿日期:2015-01-12 出版日期:2016-06-20 发布日期:2016-07-16
  • 通讯作者: 黄力宇
  • 作者简介:乔全邦(1991-),男,西安电子科技大学硕士研究生, E-mail: qqb_369927@163.com.
  • 基金资助:

    国家自然科学基金资助项目(U1401255);陕西省科学技术研究发展计划资助项目(2014K06-12);中央高校基本科研业务费专项资金资助项目(NSIY131409, JB161206)

Image reconstruction using an adaptive simultaneous algebraic reconstruction technique in computed tomography

QIAO Quanbang;HUANG Liyu;HE Zhijie   

  1. (School of Life Sciences and Technology, Xidian Univ., Xi'an  710071, China)
  • Received:2015-01-12 Online:2016-06-20 Published:2016-07-16
  • Contact: HUANG Liyu

摘要:

联合代数重建技术作为一种经典的断层图像重建算法,存在着收敛速度慢、边缘模糊、振铃效应等问题.迭代过程中与步长相关的松弛算子是影响算法性能的重要因素,而重建图像的边缘区域与其他区域无需使用相同的松弛算子,由此提出一种基于模糊熵的自适应联合代数重建算法.在进行初步的联合代数重建之后,把重建图像作为先验信息采用模糊熵的方法对其进行边缘检测,根据边缘一致性原则构造单调递增函数,以此作为定义迭代步长的松弛算子,进而可根据重建图像各部分的区域特征自适应地选取迭代步长进行接下来的联合代数迭代.仿真与实际测试实验表明,使用本改进算法进行计算机断层图像重建不仅可以较好地解决边缘模糊问题,还可以很好地抑制振铃效应.

关键词: 计算机断层成像技术, 联合代数重建技术, 模糊熵, 松弛算子

Abstract:

The simultaneous algebraic reconstruction technique(SART) is a vintage algorithm for computed tomography(CT) image reconstruction, but it has many problems such as slow convergence speed, edge blur, and ringing effect. The relaxation parameter is an important factor affecting the performance of the algorithm, and we find that the edge region does not need the same relaxation factor as the uniform region, so an adaptive simultaneous algebraic reconstruction technique based on fuzzy entropy is proposed. After preliminary SART reconstruction, by quoting fuzzy entropy for edge detection of the reconstructed image which is used as prior information, a monotonous increasing function that defines the relaxation factor is constructed based on the neighborhoodhomogeneous measurement(NHM). Therefore, the proposed approach can select the relaxation factor adaptively by the local character of the image. Experimental results show that the new algorithm can solve the problem of edge blurring and suppress the ringing effect effectively in CT image reconstruction.

Key words: computed tomography, simultaneous algebraic reconstruction technique, fuzzy entropy, relaxation factor