针对低光子泊松成像难题,提出高效贝叶斯采样新方法。
Efficient Bayesian Computation Using Plug-and-Play Priors for Poisson Inverse Problems
- 引入边界反射与泊松似然近似,加速采样收敛
- 采用黎曼几何镜像采样,避免梯度爆炸并处理非负约束
- 适合天文、医学等弱信号成像,可量化不确定性
本文研究用于低光子泊松成像的即插即用(PnP)Langevin采样策略,该类问题在天文学、医学和生物学中有重要应用。现有PnP Langevin算法在低光子条件下因解的不确定性高、正则性差(如梯度爆炸、非负约束)而表现不佳。为此,本文提出两种改进方法:(i) 带边界反射与泊松似然近似的加速PnP Langevin;(ii) 利用黎曼几何处理约束与似然不规则性的镜像采样算法。通过大量数值实验对比先进方法,验证了两者的有效性。代码已开源:https://github.com/freyyia/pnp-langevin-poisson。
原文摘要 · Abstract (English)
This paper studies plug-and-play (PnP) Langevin sampling strategies for Bayesian inference in low-photon Poisson imaging problems, a challenging class of problems with significant applications in astronomy, medicine, and biology. PnP Langevin sampling offers a powerful framework for Bayesian image restoration, enabling accurate point estimation as well as advanced inference tasks, including uncertainty quantification and visualization analyses, and empirical Bayesian inference for automatic model parameter tuning. Herein, we leverage and adapt recent developments in this framework to tackle challenging imaging problems involving weakly informative Poisson data. Existing PnP Langevin algorithms are not well-suited for low-photon Poisson imaging due to high solution uncertainty and poor regularity properties, such as exploding gradients and non-negativity constraints. To address these challenges, we explore two strategies for extending Langevin PnP sampling to Poisson imaging models: (i) an accelerated PnP Langevin method that incorporates boundary reflections and a Poisson likelihood approximation and (ii) a mirror sampling algorithm that leverages a Riemannian geometry to handle the constraints and the poor regularity of the likelihood without approximations. The effectiveness of these approaches is evaluated and contrasted through extensive numerical experiments and comparisons with state-of-the-art methods. The source code accompanying this paper is available at https://github.com/freyyia/pnp-langevin-poisson.
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