提出能量-特威迪恒等式,统一多种噪声下的去噪与得分估计。
Energy-Tweedie: Score meets Score, Energy meets Energy
- 用能量模型推广特威迪公式,建立噪声分布与得分规则的对应关系。
- 通过后验样本可直接估计得分,无需显式建模概率分布。
- 适用于生成模型训练与采样路径设计,尤其适合基于评分的生成方法。
去噪与得分估计在高斯噪声下由特威迪公式联系:后验均值与噪声边际的史坦得分相关。本文将此视角拓展至更广泛的吉布斯(能量基础)噪声分布,以广义高斯族为例。我们推导出能量-特威迪恒等式:当后验通过核评分规则视角观察时,由噪声势能定义的路径导数即恢复噪声边际的史坦得分。该评分规则的合规性仅取决于噪声势能。因此,经典中高斯噪声、后验均值、平方损失与特威迪公式的对应关系被提升为吉布斯噪声、完整后验律、核评分规则与能量-特威迪恒等式之间的分布级对应,每种噪声势能对应一个特威迪型关系。其后果包括:提供从后验样本到得分的估计路径;给出未知噪声参数的合理估计准则;支持沿用户指定噪声参数空间路径的扩散式采样,为近期基于评分规则训练的生成方法提供得分视角解释。
原文摘要 · Abstract (English)
Denoising and score estimation are classically linked through Tweedie's formula, which relates the posterior mean under Gaussian noise to the Stein score of the noisy marginal. In this work, we extend this perspective beyond Gaussian noise to a broad class of Gibbs (energy-based) noise distributions, with the generalized Gaussian family as the running example. We derive the Energy-Tweedie identity: when the denoising posterior is viewed through the lens of scoring rules, the path derivative of a kernel scoring rule defined by the noise potential recovers the Stein score of the noisy marginal. The rule's propriety is determined by the noise potential alone. Thus, the familiar correspondence between Gaussian noise, posterior means, squared loss, and Tweedie's formula is lifted to a distributional correspondence between Gibbs noise distributions, full posterior laws, kernel scoring rules, and the Energy-Tweedie identity, yielding one Tweedie-style relation for each noise potential. Among its consequences, this identity gives a posterior-samples-to-score route to score estimation, yields a principled criterion for estimating unknown noise parameters, and enables diffusion-style sampling along user-chosen paths through the noise-parameter space, supplying the score-based perspective on recent generative methods trained with scoring rules.
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