arXiv:2606.24567cs.CVphysics.med-ph2026-06

多尺度随机插件式方法加速低视角CT重建,提升效率且保持图像质量。

Multilevel Stochastic Plug-and-Play for Sparse-View CT Reconstruction

论文配图:Multilevel Stochastic Plug-and-Play for Sparse-View CT Reconstruction
图 1 · 摘自论文原文
  • 在多分辨率分析空间中设计多层级迭代,避免高成本梯度估计。
  • 实验显示重建质量接近顶尖方法,运行时间显著缩短。
  • 适合需要快速高质量重建的医学影像场景使用。

低视角计算机断层扫描(SVCT)可降低辐射剂量和采集时间,但投影视图有限导致重建问题严重不适定,使用解析方法易产生条纹伪影。插件式(PnP)方法通过结合数据保真项与学习到的图像先验有效缓解此问题,而随机化PnP方法通过重去噪匹配去噪器输入分布进一步提升鲁棒性。然而,这类方法通常需要大量迭代才能收敛,限制了实际应用效率。本文提出一种用于SVCT的多尺度(ML)随机化插件式方法(ML-SPnP),以加速随机化PnP重建。我们指出,在随机设置下,直接在各层级间强制先验一致性需通过多次去噪函数评估精确估计细粒度先验梯度,计算成本极高。受此启发,我们在多分辨率分析(MRA)逼近空间中执行多层级步骤。该选择得益于小波分解结构,使先验一致性修正在期望意义下消失,从而避免为粗层级修正代价高昂的细层级随机先验梯度估计。在SVCT重建上的实验表明,所提方法在保持与现有最先进方法相当的重建质量的同时,大幅减少运行时间。

原文摘要 · Abstract (English)

Sparse-view computed tomography (SVCT) reduces radiation exposure and acquisition time, but the limited number of projection views makes the reconstruction problem severely ill-posed and leads to streak artifacts when analytical methods are used. Plug-and-Play (PnP) methods provide an effective way to combine data fidelity with learned image priors, while stochastic PnP methods further improve robustness by matching the denoiser input distribution through re-noising. However, these methods often require many iterations to converge, which limits their practical efficiency. In this work, we propose a multilevel (ML) stochastic PnP method for SVCT that accelerates stochastic PnP reconstruction. We highlight that, in the stochastic setting, directly enforcing prior coherence across levels would require accurately estimating fine-level prior gradients through multiple denoiser function evaluations, which substantially increases the computational cost. Motivated by this observation, we perform the multilevel steps in multiresolution analysis (MRA) approximation spaces. This choice is supported by the structure of the wavelet decomposition, which causes the prior-coherence correction to vanish in expectation, thereby avoiding costly estimation of fine-level stochastic prior gradients for the coarse-level corrections. Experiments on SVCT reconstruction show that our method, called Multilevel Stochastic Plug-and-Play (ML-SPnP), achieves reconstruction quality comparable to state-of-the-art methods while substantially reducing runtime.

CT重建多尺度随机化插件式

Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。