提出一种基于压缩感知(CS)的磁共振(MR)图像重建方法.利用参考图像和目标图像结构的相似性,提取参考图像在小波域中L个大系数的索引集作为目标图像的已知支撑集,约束已知支撑集补集中小波系数的l1范数.此外,采用非局部全变差(NLTV)作为规整化项构造目标函数,通过快速合成分离算法(FCSA)重建目标图像.仿真结果证明,该方法能有效保留图像的边缘和细节信息,抑制噪声干扰,在相同采样数据量下,重建性能优于经典CS-MRI和其他同类方法.
By exploiting the similarity of the structure between the reference and the target images,a novel compressed sensing(CS)-based reconstruction method was proposed for MR image.Indexes of the Llargest wavelet coefficients of the reference image were extracted and regarded as the known part of the desired target images support,and the l1 norm of the wavelet coefficients belonging to the complement to the known support was constrained.Furthermore,the nonlocal total variation(NLTV)was utilized as a regularization term to construct the objective function.Then the target image was reconstructed via a fast composite splitting algorithm(FCSA).Experimental results demonstrate that the proposed method can preserve edges and details while suppressing noise efficiently.It outperforms conventional CS-MRI and other similar reconstruction methods under the same sampling rate.