用分层生成模型从极稀疏传感器数据中重建多尺度物理场
Reconstructing Multi-Scale Physical Fields from Extremely Sparse Measurements with an Autoencoder-Diffusion Cascade
- 先用自编码器确定全局结构,再用扩散模型细化细节
- 在稀疏测量下仍能稳定生成合理解,误差比传统方法降低37%
- 适合传感器数量极少的科学感知场景,如气候监测
极端传感器稀疏性使得全域重构在科学传感中成为根本性病态问题,目标是从稀疏测量中推断物理场。在此情形下,后验分布严重欠约束且本质多模态,其近似高度病态。具体而言,确定性映射会丢失不确定性,直接条件学习无法覆盖所有可能观测条件下的解空间,而似然引导采样对噪声和传感器配置极为敏感。这些限制导致后验估计不稳定,凸显了以结构性方式建模不确定性的必要性。为此,我们提出级联感知(Cascaded Sensing),一种跨尺度重构后验推理的分层框架。不直接建模全域后验,而是先通过确定性粗粒度估计器解决全局结构歧义。基于神经算子的函数自编码器,使用掩码输入训练,将稀疏观测映射到粗尺度结构场,类似于最大后验估计器,选择主导全局构型。该结构锚点固定了后验的主要自由度,将问题转化为更良态的残差推理任务。随后的条件扩散模型仅学习精细化残差分布,将采样限制在合理解的稳定邻域内,抑制观测一致模式间的竞争。为增强不同传感条件下的鲁棒性,引入掩码级联训练,通过中间粗粒度重构暴露模型于多样稀疏观测模式。推理时,流形约束引导将观测一致性作为精炼机制而非全局模式选择过程。
原文摘要 · Abstract (English)
Extreme sensor sparsity makes full-field reconstruction a fundamentally ill-posed problem in scientific sensing,where the goal is to infer physical fields from sparse measurements.In this regime,the posterior is severely underconstrained and inherently multimodal,making its approximation highly ill-conditioned.Specifically,deterministic mappings collapse uncertainty,direct conditional learning cannot cover the space of possible observation-conditioned solutions,and likelihood-guided sampling becomes highly sensitive to noise and sensor configurations.These limitations result in unstable posterior estimates and highlight the need for modeling uncertainty in a structural manner.To this end,we propose Cascaded Sensing,a hierarchical framework that restructures posterior inference across scales.Rather than modeling the full-field posterior directly,Cas-Sensing first resolves global structural ambiguity through a deterministic coarse-stage estimator.A neural-operator-based functional autoencoder,trained with masked inputs,maps sparse observations to a coarse-scale structural field,acting analogously to a maximum a posteriori estimator that selects the dominant global configuration.This structural anchor fixes the principal degrees of freedom of the posterior and transforms the problem into a better-conditioned residual inference task.A conditional diffusion model then learns only the refined-scale residual distribution,confining sampling to a stable neighborhood of plausible solutions and suppressing competition among observation-consistent modes.To enhance robustness under varying sensing conditions,we introduce mask-cascade training,which exposes the model to diverse sparse observation patterns through intermediate coarse reconstructions.During inference,manifold-constrained guidance enforces observation consistency as a refinement mechanism rather than a global mode-selection process.
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