arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2305.04775eess.IV
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多尺度能量(MuSE)即插即用框架用于逆问题

Multi-Scale Energy (MuSE) plug and play framework for inverse problems

Jyothi Rikhab Chand, Mathews Jacob

AI总结:

本文提出多尺度能量(MuSE)即插即用框架,通过显式或隐式多尺度能量模型学习图像先验,用于逆问题中的MAP估计与后验采样,在MR图像恢复中达到与端到端模型相当的重建质量,且对前向模型变化稳健,并支持不确定性估计。

摘要:

我们引入多尺度能量模型来学习图像的先验分布,该模型可用于逆问题中以推导最大后验(MAP)估计并从后验分布中采样。与传统的单尺度能量模型相比,多尺度策略提高了MAP算法的估计精度和收敛性,即使初始化远离解时也是如此。我们提出了两种多尺度策略:a) 显式(e-MuSE)框架,其中我们使用一系列显式能量,每个能量对应原始负对数先验的光滑近似;b) 隐式(i-MuSE)框架,其中我们依赖单一能量函数,其在不同尺度上的梯度与相应的e-MuSE梯度紧密匹配。尽管两种方案都提高了收敛性和精度,但e-MuSE的MAP解依赖于调度策略,包括中间尺度的选择和退出条件。相比之下,i-MuSE公式显著更简单,导致更快的收敛和更好的性能。我们在磁共振(MR)图像恢复的背景下比较了所提出的MuSE模型的性能。结果表明,多尺度框架产生的MAP重建质量与端到端(E2E)训练模型相当,同时相对不受前向模型变化的影响。此外,i-MuSE方案还允许从后验分布生成样本,使我们能够估计不确定性图。

英文摘要:

We introduce multi-scale energy models to learn the prior distribution of images, which can be used in inverse problems to derive the Maximum A Posteriori (MAP) estimate and to sample from the posterior distribution. Compared to the traditional single-scale energy models, the multi-scale strategy improves the estimation accuracy and convergence of the MAP algorithm, even when it is initialized far away from the solution. We propose two kinds of multi-scale strategies: a) the explicit (e-MuSE) framework, where we use a sequence of explicit energies, each corresponding to a smooth approximation of the original negative log-prior, and b) the implicit (i-MuSE), where we rely on a single energy function whose gradients at different scales closely match the corresponding e-MuSE gradients. Although both schemes improve convergence and accuracy, the e-MuSE MAP solution depends on the scheduling strategy, including the choice of intermediate scales and exit conditions. In contrast, the i-MuSE formulation is significantly simpler, resulting in faster convergence and improved performance. We compare the performance of the proposed MuSE models in the context of Magnetic Resonance (MR) image recovery. The results demonstrate that the multi-scale framework yields a MAP reconstruction comparable in quality to the End-to-End (E2E) trained models, while being relatively unaffected by the changes in the forward model. In addition, the i-MuSE scheme also allows the generation of samples from the posterior distribution, enabling us to estimate the uncertainty maps.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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