ISSN 1004-4140
    CN 11-3017/P

    基于双重正则化项的稀疏角能谱CT图像重建算法研究

    Dual Regularization-Based Sparse-View Spectral CT Image Reconstruction Algorithm

    • 摘要: 能谱CT(Spectral Computed Tomography, Spectral CT)技术是一种新兴的成像技术,通过采集多能谱投影数据,提升了物质区分能力和临床诊断准确性。然而,稀疏角扫描条件下的能谱CT图像重建仍然面临着噪声抑制和边缘保护的挑战。正则化方法能够引入先验信息提升稀疏角能谱CT图像重建质量,如方向概率全变差(Directional Probabilistic Total Variation, dTV-p)正则化和紧小波框架L0正则化。为了抑制噪声、保护边界,本文提出了一种基于dTV-p和紧小波框架L0的双重正则化稀疏角能谱CT图像重建算法,并利用快速迭代收缩阈值算法(Fast Iterative Shrinkage-Thresholding Algorithm, FISTA)进行加速。首先,该方法在图像域对dTV-p正则化采用近端映射和FISTA进行求解。随后,在小波域对L0正则化采用迭代硬阈值法进行求解。最后,对对偶变量进行FISTA加速求解。通过实验验证所提算法的有效性,实验结果表明所提算法在边缘保护、噪声抑制和定量评价指标方面均优于对比算法。

       

      Abstract: Spectral Computed Tomography (Spectral CT) is an emerging imaging technology that enhances material differentiation and clinical diagnostic accuracy by acquiring multi-spectral projection data. However, in sparse-angle spectral CT image reconstruction, noise suppression and edge preservation still face challenges. Regularization methods, such as Directional Probabilistic Total Variation (dTV-p) and tight wavelet frame L0, could introduce prior information to improve sparse-angle spectral CT image reconstruction quality. In this study, we propose a dTV-p and tight wavelet frame L0 regularization-based dual-regularization sparse-angle spectral CT image reconstruction algorithm to address noise suppression and edge preservation. We used the fast iterative shrinkage-thresholding algorithm (FISTA) to accelerate the algorithm. First, the dTV-p regularization is solved in the image domain using proximal mapping and FISTA. Next, the L0 regularization is solved in the wavelet domain using iterative hard thresholding. Finally, the dual variables are solved using FISTA acceleration. The experimental results demonstrated the efficacy of the proposed algorithm, revealing superior performance in edge preservation, noise suppression, and quantitative evaluation metrics compared to comparative algorithms.

       

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