Extraction of respiratory activity from photoplethysmographic signals based on an independent component analysis technique: Preliminary report

Yongjin Zhou, Yongping Zheng, Congzhi Wang, Junfeng Yuan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

13 Citations (Scopus)


A new method is reported for monitoring respiratory activity using photoplethysmography (PPG) without the need of prior knowledge of the respiratory rate range. Two channels of transmission mode PPG signals were collected from the subject's index finger and analyzed using an independent component analysis (ICA) algorithm. The respiratory activity was separated from the heart-related pulsation in PPG after the ICA analysis. The results demonstrated that the ICA analysis could successfully extract normal and simulated apnoea respiratory activities. The algorithm was applied for both simulated signals and those collected from 10 young normal adults. The reported technique may be potentially used for the simultaneous monitoring of the pulse rate and respiratory activity based on the hardware of current pulse oximetry devices. The structure and implementation of this preliminary respiratory activity monitoring system were presented. Possible further improvements for the system performance were also discussed.
Original languageEnglish
Pages (from-to)537-545
Number of pages9
JournalInstrumentation Science and Technology
Issue number5
Publication statusPublished - 1 Oct 2006


  • Apnoea
  • ICA
  • Independent component analysis
  • Photoplethysmography
  • PPG
  • Pulse oximetry
  • Respiration

ASJC Scopus subject areas

  • Analytical Chemistry
  • Instrumentation

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