Reconsider photoplethysmogram signal quality assessment in the free living environment

Yan Wei Su, Chia Cheng Hao, Gi Ren Liu, Yuan Chung Sheu, Hau Tieng Wu

Research output: Contribution to journalComment/debatepeer-review


Objective. Assessing signal quality is crucial for biomedical signal processing, yet a precise mathematical model for defining signal quality is often lacking, posing challenges for experts in labeling signal qualities. The situation is even worse in the free living environment. Approach. We propose to model a PPG signal by the adaptive non-harmonic model (ANHM) and apply a decomposition algorithm to explore its structure, based on which we advocate a reconsideration of the concept of signal quality. Main results. We demonstrate the necessity of this reconsideration and highlight the relationship between signal quality and signal decomposition with examples recorded from the free living environment. We also demonstrate that relying on mean and instantaneous heart rates derived from PPG signals labeled as high quality by experts without proper reconsideration might be problematic. Significance. A new method, distinct from visually inspecting the raw PPG signal to assess its quality, is needed. Our proposed ANHM model, combined with advanced signal processing tools, shows potential for establishing a systematic signal decomposition based signal quality assessment model.

Original languageEnglish (US)
Article number06NT01
JournalPhysiological Measurement
Issue number6
StatePublished - Jun 1 2024


  • free-living environment
  • photoplethysmogram
  • signal quality index
  • synchrosqueezing transform

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Biomedical Engineering
  • Physiology (medical)


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