arXiv:2505.04820eess.IVcs.NA2025-05被引 1

提出新型快速收敛的复数拟牛顿算法,提升压缩感知MRI重建精度与速度。

Convergent Complex Quasi-Newton Proximal Methods for Gradient-Driven Denoisers in Compressed Sensing MRI Reconstruction

  • 基于梯度驱动去噪器设计复数域拟牛顿近似方法,改进收敛性。
  • 在笛卡尔与非笛卡尔采样下均实现更快重建,比现有方法提速显著。
  • 理论证明适用于非凸场景,适合医学图像重建研究者使用。

在压缩感知(CS)MRI中,模型驱动方法对实现高精度重建至关重要。其核心挑战在于如何有效描述目标图像的统计分布。插件式(PnP)和通过去噪进行正则化(RED)是利用去噪器作为先验的通用框架。尽管基于卷积神经网络(CNN)的去噪器在CS MRI中表现优于传统手工设计的先验,但其收敛性理论依赖于不适用于实际CNN的假设。最近提出的梯度驱动去噪器为实际性能与理论保证之间提供了桥梁。然而,相关最小化问题的数值求解器在CS MRI重建中仍显缓慢。本文提出一种复数拟牛顿近似方法,实现了比现有方法更快的收敛速度。针对CS MRI中的复数域特性,我们设计了一种保证赫米特正定性的修正海森矩阵估计方法。此外,我们对所提方法在非凸设置下的收敛性进行了严格分析。在笛卡尔与非笛卡尔采样轨迹上的数值实验验证了该方法的有效性与高效性。

原文摘要 · Abstract (English)

In compressed sensing (CS) MRI, model-based methods are pivotal to achieving accurate reconstruction. One of the main challenges in model-based methods is finding an effective prior to describe the statistical distribution of the target image. Plug-and-Play (PnP) and REgularization by Denoising (RED) are two general frameworks that use denoisers as the prior. While PnP/RED methods with convolutional neural networks (CNNs) based denoisers outperform classical hand-crafted priors in CS MRI, their convergence theory relies on assumptions that do not hold for practical CNNs. The recently developed gradient-driven denoisers offer a framework that bridges the gap between practical performance and theoretical guarantees. However, the numerical solvers for the associated minimization problem remain slow for CS MRI reconstruction. This paper proposes a complex quasi-Newton proximal method that achieves faster convergence than existing approaches. To address the complex domain in CS MRI, we propose a modified Hessian estimation method that guarantees Hermitian positive definiteness. Furthermore, we provide a rigorous convergence analysis of the proposed method for nonconvex settings. Numerical experiments on both Cartesian and non-Cartesian sampling trajectories demonstrate the effectiveness and efficiency of our approach.

MRI重建压缩感知优化算法去噪器

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