用物理约束神经网络和共形映射,从噪声图像中同时重建血流与血管形状。
Coupled Reconstruction of 2D Blood Flow and Vessel Geometry from Noisy Images via Physics-Informed Neural Networks and Quasi-Conformal Mapping
- 分两步优化:先用物理神经网络恢复流速场,再通过共形映射推断真实血管几何。
- 在含高斯噪声的合成数据和带信号依赖噪声的真实血管数据上均有效提升重建质量。
- 适合医学影像处理、血流动力学分析及低质量影像修复场景。
血流成像对血管系统内的血流动态行为具有重要信息价值,是医疗诊断与治疗规划的关键。然而,高质量流速图像的获取仍面临挑战,尤其在采集时间短或设备误差导致的伪影情况下。本文针对此类噪声图像的去噪问题,将其建模为优化任务:最小化满足纳维-斯托克斯方程的模拟速度场与观测到的噪声速度数据之间的差异。方法将问题分解为两个子问题:流体子问题利用物理信息神经网络(PINN)在固定域下重构速度场;几何子问题则通过优化拟共形映射来推断真实的流体区域。两者采用交替高斯-赛德尔算法迭代求解,持续优化速度场与域形。实验验证了该框架在收敛通道几何下的合成数据(不同水平高斯噪声)以及主动脉几何下的真实类数据(信号依赖噪声)中的有效性与鲁棒性。消融实验进一步评估了关键超参数的影响。
原文摘要 · Abstract (English)
Blood flow imaging provides important information for hemodynamic behavior within the vascular system and plays an essential role in medical diagnosis and treatment planning. However, obtaining high-quality flow images remains a significant challenge. In this work, we address the problem of denoising flow images that may suffer from artifacts due to short acquisition times or device-induced errors. We formulate this task as an optimization problem, where the objective is to minimize the discrepancy between the modeled velocity field, constrained to satisfy the Navier-Stokes equations, and the observed noisy velocity data. To solve this problem, we decompose it into two subproblems: a fluid subproblem and a geometry subproblem. The fluid subproblem leverages a Physics-Informed Neural Network to reconstruct the velocity field from noisy observations, assuming a fixed domain. The geometry subproblem aims to infer the underlying flow region by optimizing a quasi-conformal mapping that deforms a reference domain. These two subproblems are solved in an alternating Gauss-Seidel fashion, iteratively refining both the velocity field and the domain. Upon convergence, the framework yields a high-quality reconstruction of the flow image. We validate the proposed method through experiments on synthetic flow data in a converging channel geometry under varying levels of Gaussian noise, and on real-like flow data in an aortic geometry with signal-dependent noise. The results demonstrate the effectiveness and robustness of the approach. Additionally, ablation studies are conducted to assess the influence of key hyperparameters.
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