Paperdoi:10.3390/bioengineering13101231

Multispectral PPG Sensing Framework for Noninvasive Glucose Prediction via Multi-Feature Fusion and Micro-Environmental Compensation

Venue listed2026Added Oct 22, 2026

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Authors: Huang Lin, Jie Wang, Yuanshuang Fan, Jiansen Lan, Haijun Luo, Rui Wang

Bioengineering 13(10):1231 (MDPI), published 2026-10-21

Licence: CC BY (OpenAlex)

TL;DR

Finger clip with four NIR wavelengths (940, 1300, 1550, 1650 nm) plus contact-site temperature and relative humidity sensors. 39 features: optical ratios, pulse morphology, frequency descriptors, participant characteristics and environment; six regressors, XGBoost best; SHAP attribution.

  • Form factor: finger

Abstract

Noninvasive blood glucose prediction using near-infrared spectroscopy remains challenging due to weak glucose-specific absorption, tissue variability, and environmental interference. This study proposes a multispectral photoplethysmography (PPG)-based framework integrating multi-feature fusion, local temperature and humidity compensation, and machine learning regression. The system employs four near-infrared wavelengths (940, 1300, 1550, and 1650 nm) while simultaneously measuring finger contact-site temperature (T) and local relative humidity (H) within the finger clip. A 39-dimensional feature set incorporating optical ratios, pulse-wave morphology, frequency-domain descriptors, participant characteristics, and environmental parameters was constructed. Among six optimized regression models, Extreme Gradient Boosting (XGBoost) achieved the best performance in group-isolated 10-fold cross-validation, with R2 = 0.9135, root mean square error (RMSE) = 0.2991, and mean absolute relative difference (MARD) = 2.71%. Clarke error grid analysis (CEGA) showed that 97% of predictions fell within zone A and 100% within zones A and B. Feature ablation demonstrated that local temperature and humidity measurements improved prediction accuracy, with humidity providing a greater improvement than temperature. SHapley Additive exPlanations (SHAP) analysis quantified the contributions of optical, environmental, and participant-level features. A separate session-holdout evaluation yielded R2 = 0.7261 and MARD = 6.07%. These findings highlight the potential of the proposed framework for noninvasive glucose prediction. However, the small, predominantly healthy cohort and limited glucose range constrain generalizability, necessitating validation in larger, more diverse populations to establish performance in previously unseen participants and assess clinical applicability.

Verbatim from the publisher's DOI record (opens in a new tab) · Publisher licence: https://creativecommons.org/licenses/by/4.0/

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Tasks & signals

Tasks

Glucose

Keywords

glucosemulti-wavelengthNIRfinger-cliptemperature-compensationhumidity-compensationXGBoostSHAPClarke-error-gridskeptical

How it works

How Method works: Setup → Method → TargetSetup: Signals (PPG (multispectral NIR), skin temperature, humidity); Wavelengths (940 nm, 1300 nm, 1550 nm, 1650 nm); Form factor (finger). Method: Method (Gradient-boosted trees · Contrastive learning). Target: Glucose.SetupSignals: PPG (multispectral NIR), skin temperature, humiditySignalsPPG (multispectral NIR), skin…Wavelengths: 940 nm, 1300 nm, 1550 nm, 1650 nmWavelengths940 nm, 1300 nm, 1550 nm, 1650 nmForm factor: fingerForm factorfingerMethodMethodGradient-boosted trees ·…TargetGlucoseGlucose
Wavelengths
940 nm, 1300 nm, 1550 nm, 1650 nm

Cite this paper

APA

Lin, H., Wang, J., Fan, Y., Lan, J., Luo, H., & Wang, R. (2026). Multispectral PPG Sensing Framework for Noninvasive Glucose Prediction via Multi-Feature Fusion and Micro-Environmental Compensation. Bioengineering. https://doi.org/10.3390/bioengineering13101231

BibTeX

@article{lin2026multispectral,
  title         = {{Multispectral PPG Sensing Framework for Noninvasive Glucose Prediction via Multi-Feature Fusion and Micro-Environmental Compensation}},
  author        = {Lin, Huang and Wang, Jie and Fan, Yuanshuang and Lan, Jiansen and Luo, Haijun and Wang, Rui},
  year          = {2026},
  journal       = {Bioengineering},
  doi           = {10.3390/bioengineering13101231}
}

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