A Comprehensive Inference-Time Augmentation Framework in Physiological Signals: Application to PPG-Based AF Detection
生理信号中的综合推理时增强框架:应用于基于PPG的房颤检测
Davood Fattahi, Runze Yan, Saurabh Kataria, Zhaoliang Chen, Xiao Hu
AI总结 提出一个包含13种增强方法的统一推理时增强框架,通过贝叶斯优化超参数,在PPG房颤检测任务中显著提升AUROC和AUPRC,降低假阳性率。
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- 22 pages, 11 figures, 4 tables. Under review at Physiological Measurement
目标:在真实部署中,生理信号的准确分类面临传感器噪声、运动伪影以及训练数据与部署数据之间分布偏移的挑战。推理时增强(ITA)在推理过程中应用增强而非重新训练,提供了一种简单、模型无关的机制来提高鲁棒性。然而,ITA在生理信号中的应用范围仍然狭窄,依赖于有限的增强方法和固定的未优化参数。本文提出一个统一的ITA框架以解决这一差距。方法:该框架包含13种增强方法,涵盖时域、幅值域、频域和伪影注入变换,并通过贝叶斯优化优化超参数。我们使用GPT-PPG和ResNet在五个数据集(包含400多名患者和约9,800小时记录)上评估基于30秒PPG信号的房颤(AF)检测。主要结果:标准ITA持续改善了AUROC(GPT-PPG最高提升8.5%,ResNet最高提升0.7%)和AUPRC(GPT-PPG最高提升10.6%,ResNet最高提升0.8%)。选择性ITA进一步将非AF数据集上的平均FPR降低了高达4.4%(GPT-PPG)和1.3%(ResNet)。意义:这些发现确立了ITA作为一种实用的、模型无关的方法,用于在无法重新训练的部署环境中提高基于PPG的房颤分类可靠性,并具有更广泛的生理信号分析适用性。
Objective: Accurate classification of physiological signals in real-world deployments is challenged by sensor noise, motion artifacts, and distribution shifts between training and deployment data. Inference-time augmentation (ITA), which applies augmentations during inference rather than retraining, offers a simple, model-agnostic mechanism to improve robustness. However, ITA application to physiological signals has remained narrow in scope, relying on limited augmentation methods with fixed, unoptimized parameters. This work proposes a unified ITA framework to address that gap. Approach: The framework incorporates 13 augmentation methods spanning time-domain, amplitude-domain, frequency-domain, and artifact-injection transformations, with hyperparameters optimized via Bayesian optimization. We evaluate on atrial fibrillation (AF) detection from 30-second PPG signals using GPT-PPG and ResNet across five datasets comprising more than 400 patients and ${\sim}$9,800 hours of recording. Main results: Standard ITA consistently improved AUROC (up to 8.5% for GPT-PPG and 0.7% for ResNet) and AUPRC (up to 10.6% for GPT-PPG and 0.8% for ResNet). Selective ITA further reduced average FPR by up to 4.4% (GPT-PPG) and 1.3% (ResNet) on non-AF datasets. Significance: These findings establish ITA as a practical, model-agnostic approach for improving PPG-based AF classification reliability in deployment settings where retraining is not feasible, with broader applicability to physiological signal analysis.