Generalizable PPG Signal Quality Assessment Using Correlation-Derived Morphological Features

Unsupervised Photoplethysmography Signal Quality Assessment using Contrastive Learning and Persistent Homology

Feature Stability of PPG Morphological Descriptors Across Diverse Clinical Acquisition Settings

A Comparative Analysis of Signal Quality and Morphological Fidelity in ECG Smartwatches

This study provides a direct and objective comparison of ECG signal quality and morphological feature preservation across four leading commercial smartwatches: the Apple Watch Series 9, Samsung Galaxy Watch 6, Fitbit Sense 2, and Withings ScanWatch, using a controlled dataset. The Philips TC30 is used as the reference...

Photoplethysmography-Based Assessment of Mental Stress: Stroop Test Analysis Using Public and IoT Data

Photoplethysmography (PPG) serves as a non-invasive technique for assessing an individual’s physiological state, including stress. Cognitive tasks typically alter this state compared to a pre-test baseline. Specifically, the Stroop test is recognized for modifying sympathetic nervous system activity and ventricular rep...

Interpretable Reliability Control for Wearable PPG Heart Rate Estimation

Wearable photoplethysmography (PPG) can return a plausible heart rate (HR) after motion or poor optical coupling has made the measurement unreliable. We treat HR reporting as a reliability-control problem and introduce an interpretable signal quality index (SQI) layer that reports coverage and residual error. On PPG-Da...

Real-Time SpO2 Estimation from Chest Reflectance Photoplethysmography: Algorithm Development and Clinical Validation Against Arterial SaO2

A real-time SpO2 estimation algorithm based on chest reflectance PPG that supports the technical feasibility of chest reflectance PPG-based SpO2 estimation and its accuracy under controlled desaturation conditions is developed and clinically evaluated.