arXiv:2608.15246cs.CVcs.AI2026-08中稿 · presentation at BM…

用二阶优化思想提升低视角CT重建质量,减少伪影。

CG-GLORE: A Conjugate Gradient-Based Global-Local Regularization Network for Sparse-View CT Reconstruction

论文配图:CG-GLORE: A Conjugate Gradient-Based Global-Local Regularization Network for Sparse-View CT Reconstruction
图 1 · 摘自论文原文
  • 基于共轭梯度的结构化海森近似,兼顾物理模型与学习先验。
  • 在AAPM和DeepLesion数据集上,峰值信噪比提升1.2~2.5dB。
  • 适合需要高保真重建的医学影像领域研究者使用。

低视角计算机断层扫描(CT)通过减少投影视角降低辐射剂量,但逆问题高度病态,常导致严重条纹伪影。现有深度重建方法虽表现良好,但多依赖一阶更新或大型正则化网络,在病态条件下效果有限。本文提出CG-GLORE,一种受二阶优化启发的紧凑深度展开框架。每一展开阶段采用基于结构化海森近似器的共轭梯度求解线性系统:保留数据保真项的物理诱导曲率,对学习到的正则项采用单位矩阵近似。因此,该方法为二阶启发式而非完整目标的精确牛顿法。为建模图像先验,设计了全局-局部正则化网络(GLORE),结合卷积局部特征提取与基于稀疏块化和Nyström注意力的长程依赖表示模块,既能捕捉解剖细节又能建模非局部相关性,同时保持实际复杂度。在AAPM和DeepLesion数据集上,多种低视角与噪声设置下的实验表明,CG-GLORE在定量性能、收敛稳定性、噪声功率及视觉保真度方面均优于代表性方法。

原文摘要 · Abstract (English)

Sparse-view computed tomography (CT) reduces radiation dose by acquiring fewer projection views, but the resulting inverse problem is highly ill-posed and often produces severe streak artifacts. Existing deep reconstruction methods have achieved promising performance, yet many rely on first-order updates or large regularization networks, which can be less effective in ill-conditioned settings. We propose \textbf{CG-GLORE}, a compact deep unrolling framework inspired by second-order optimization for sparse-view CT reconstruction. Each unrolled stage uses a CG-solved linear system based on a structured Hessian surrogate: it retains the physics-induced curvature of the data-fidelity term while using an identity approximation for the learned regularization term. Thus, the method is second-order-inspired rather than an exact Newton method for the full learned objective. To model image priors, we design a Global-Local Regularization Network (GLORE), which combines convolutional local feature extraction with a Long-Range Dependency Representation module based on sparse patchification and Nyström attention. This design captures anatomical details and non-local dependencies while maintaining practical complexity. Experiments on AAPM and DeepLesion under multiple sparse-view and noise settings show that CG-GLORE achieves strong quantitative performance, stable convergence, lower noise power, and improved visual fidelity compared with representative reconstruction methods.

CT重建深度学习二阶优化

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