PaperarXiv:2607.07996

SpO2 Predictor-Guided Stage-Wise Time-Frequency Reconstruction of Low-Quality Dual-Wavelength PPG for Oxygen Saturation Estimation

Preprint2026Added Sep 26, 2026

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Authors: Zequan Liang, Elahe Hosseini, Ning Miao, Mahdi Pirayesh Shirazi Nejad, Wei Shao, Ehsan Kourkchi et al. (8 authors)

arXiv preprint (eess.SP, cs.AI, cs.LG)

First page or project page of “SpO2 Predictor-Guided Stage-Wise Time-Frequency Reconstruction of Low-Quality Dual-Wavelength PPG for Oxygen Saturation Estimation” (opens in a new tab)

Liang, Zequan et al., "SpO$_2$ Predictor-Guided Stage-Wise Time-Frequency Reconstruction of Low-Quality Dual-Wavelength PPG for Oxygen Saturation Estimation", arXiv:2607.07996, CC BY 4.0

TL;DR

Continuous oxygen saturation (SpO$2$) estimation from wearable photoplethysmography (PPG) is important for long-term health monitoring, but low-quality red and infrared PPG segments can distort waveform morphology and degrade SpO$2$ prediction accuracy. Existing PPG denoising and reconstruction methods usually optimize waveform fidelity or heart rate characteristics, while time-domain waveform loss on PPG signals alone insufficiently preserves frequency structure and SpO$2$-relevant information. This paper proposes a SpO$2$ predictor-guided stage-wise time-frequency reconstruction framework for low-quality dual-wavelength PPG signals.

  • Form factor: wrist

Abstract

Continuous oxygen saturation (SpO_2) estimation from wearable photoplethysmography (PPG) is important for long-term health monitoring, but low-quality red and infrared PPG segments can distort waveform morphology and degrade SpO_2 prediction accuracy. Existing PPG denoising and reconstruction methods usually optimize waveform fidelity or heart rate characteristics, while time-domain waveform loss on PPG signals alone insufficiently preserves frequency structure and SpO_2-relevant information. This paper proposes a SpO_2 predictor-guided stage-wise time-frequency reconstruction framework for low-quality dual-wavelength PPG signals. The proposed method first selects high-quality PPG segments to pretrain a SpO_2 predictor. A masked reconstruction model is then trained to recover randomly masked PPG regions using a joint reconstruction objective that combines time-domain waveform loss with frequency-domain loss computed from the short-time Fourier transform (STFT). To make the reconstruction task physiologically relevant, the pretrained SpO_2 predictor is incorporated as an additional constraint, encouraging the reconstructed PPG to preserve SpO_2 information rather than only minimizing waveform reconstruction error. The SpO_2 predictor and PPG reconstructor model are optimized through four training stages. Experiments on the public OpenOximetry Repository and a private wearable PPG dataset show that the proposed approach achieves the lowest subject-level MAE, with 2.882% on the public dataset and 2.359% on the private dataset.

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Tasks & signals

Tasks

SpO₂Signal denoisingSignal quality

Signals

Keywords

SpO2reconstructiondual-wavelengthlow-quality

How it works

How Method works: Setup → Method → TargetSetup: Signals (PPG); Wavelengths (red, IR); Form factor (wrist). Method: Method (Masked reconstruction). Target: SpO₂; Signal denoising; Signal quality.SetupSignals: PPGSignalsPPGWavelengths: red, IRWavelengthsred, IRForm factor: wristForm factorwristMethodMASK → RECONSTRUCTMethodMasked reconstructionTargetSpO₂O₂SpO₂Signal denoisingSignal denoisingSignal qualitySignal quality
Wavelengths
red, IR

Cite this paper

APA

Liang, Z., Hosseini, E., Miao, N., Nejad, M. P. S., Shao, W., Kourkchi, E., et al. (2026). SpO2 Predictor-Guided Stage-Wise Time-Frequency Reconstruction of Low-Quality Dual-Wavelength PPG for Oxygen Saturation Estimation. arXiv preprint. https://doi.org/10.48550/arXiv.2607.07996

BibTeX

@misc{liang2026spo2,
  title         = {{SpO2 Predictor-Guided Stage-Wise Time-Frequency Reconstruction of Low-Quality Dual-Wavelength PPG for Oxygen Saturation Estimation}},
  author        = {Liang, Zequan and Hosseini, Elahe and Miao, Ning and Nejad, Mahdi Pirayesh Shirazi and Shao, Wei and Kourkchi, Ehsan and others},
  year          = {2026},
  howpublished  = {arXiv preprint},
  doi           = {10.48550/arXiv.2607.07996},
  eprint        = {2607.07996},
  archivePrefix = {arXiv}
}

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