摘要
超声衍射层析成像(UDT)具有分辨率高、对致密组织敏感等特点,具有很高的临床应用价值。为了抑制伪影,提高图像重建质量,传统的插值算法需要大量的投影次数和采集通道数量,导致成像耗时,系统复杂。本文提出一种基于压缩感知(CS)的重建算法,在有限次投影条件下,实现图像的高质量重建。首先用平面波从随机选取的角度以有限次数照射目标,依据傅里叶衍射投影定理,获得目标空间频率采样值。然后,通过研究目标在变换域的稀疏性,根据压缩感知原理,构建目标重建的逆问题。最后,通过共轭梯度算法解逆问题,重建目标。实验结果表明,通过压缩感知,在有限次投影情形和较少采集通道情况下,提出的方法能够准确重建目标。这不仅能够节省成像扫描时间,避免组织运动带来影像失真,还能够减少系统复杂度,降低设备成本。与传统的插值算法相比,本文的方法能够有效地降低重建误差,提高结构相似度。
Ultrasound diffraction tomography （UDT） possesses the characteristics of high resolution, sensitive to dense tissue, and has high application value in clinics. To suppress the artifact and improve the quality of reconstruc- ted image, classical interpolation method needs to be improved by increasing the number of projections and channels, which will increase the scanning time and the complexity of the imaging system. In this study, we tried to accurately reconstruct the object from limited projection based on compressed sensing. Firstly, we illuminated the object from random angles with limited number of projections. Then we obtained spatial frequency samples through Fourier dif- fraction theory. Secondly, we formulated the inverse problem of UDT by exploring the sparsity of the object. Third- ly, we solved the inverse problem by conjugate gradient method to reconstruct the object. We accurately reconstruc- ted the object using the proposed method. Not only can the proposed method save scanning time to reduce the distor- tion by respiratory movement, but also can reduce cost and complexity of the system, Compared to the interpolation method, our method can reduce the reconstruction error and improve the structural similarity.
出处
《生物医学工程学杂志》
EI
CAS
CSCD
北大核心
2015年第5期975-982,共8页
Journal of Biomedical Engineering
基金
国家973项目资助(2011CB933103)
国家"十二五"科技支撑计划资助(2012BAI13B020)
关键词
压缩感知
超声衍射层析成像
图像重建
逆问题
compressed sensing
ultrasound diffraction tomography
image reconstruction
inverse problem
