用生成模型优化压缩感知采样策略,提升图像重建与MRI加速效果。
Flow-Based Generative Modeling for Optimizing Sampling Policies in Compressed Sensing Applications

- 基于流模型学习任务感知的采样掩码,动态优化采样过程。
- 在5%采样率下,CelebA图像重建达到25.17 dB PSNR;8×加速MRI达29.24 dB。
- 适用于图像分类、重建及MRI加速,计算开销极低,适合实际部署。
信号处理与医学成像中的众多现代应用面临资源受限下的高维信号采集难题。传统采样理论要求测量数与信号环境维度成正比,常不切实际。压缩感知通过稀疏性突破此限制,仅需满足特定条件的测量算子即可实现信号恢复。本研究提出一种面向任务的流模型生成框架,将传统流匹配训练范式重构为优化压缩感知采样策略的方法。该框架可学习采样掩码,在图像分类、图像重建和MRI加速任务中显著提升性能。图像重建任务中,于CelebA数据集以5%采样率实现25.17 dB PSNR;在fastMRI数据集上对8×加速的MRI测量实现29.24 dB PSNR,且计算开销极小。结果验证了生成流模型中任务条件化设计的有效性,揭示了新型表征学习方向。整体框架提供统一灵活的方案,可推广至多种逆问题场景。
原文摘要 · Abstract (English)
Numerous modern applications in signal processing and medical imaging necessitate acquiring high-dimensional signals under tight resource constraints. Traditional sampling theory suggests that accurate signal reconstruction requires a number of measurements proportional to the signal's ambient dimension, a requirement often too expensive or impractical. Compressed sensing challenges this notion by demonstrating that sparse signals can be recovered with fewer measurements, provided the measurement operator meets certain conditions. This proof-of-concept study presents a task-aware flow-based generative framework -- a reformulation of the conventional Flow Matching training paradigm with a flow model trained to optimize subsampling in compressed sensing applications. We establish the fundamental feasibility of the proposed framework of learning subsampling masks that substantially enhance the performance of compressed sensing for image classification, image reconstruction, and MRI acceleration. For the image reconstruction task, our method demonstrated state-of-the-art performance, achieving Peak Signal-to-Noise Ratio of 25.17 dB at the subsampling rate of 5\% on the CelebA dataset and 29.24 dB when reconstructing $8\times$ accelerated MRI measurements (fastMRI dataset) with the minimal computational overhead. These results highlight the effectiveness of task-conditioning within generative flow models and reveal a promising direction for representation learning strategies. Overall, the proposed framework offers a unified, flexible approach to designing data- and task-driven sensing schemes that can be potentially adapted to a broad range of inverse problems.
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