Exploring the usage of time-of-flight cameras for contact and remote photoplethysmography

Caterina Nahler, Bernhard Feldhofer, Matthias Ruether, Gerald Holweg, Norbert Druml

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


The heart beat is one of the basic vital signs, but the pulse wave can communicate much more information than the beat frequency of the heart. Through the heart rate variability (HRV) among other things, stress level and drowsiness can be inferred. Reliable HRV measurements are commonly obtained by electrocardiography (ECG). In this paper we analyse the correlation between HRV and pulse rate variability (PRV) obtained from contact or remote photoplethysmography (PPG) on a Time-of-Flight (ToF) camera from PMD Technologies AG. The ToF camera is independent of passive illumination as it uses an infrared (IR) light source, which is invisible to the human eye. Therefore, potential use cases include driver monitoring or convenient heart rate measurement with smart phones. We will demonstrate methods for using a ToF camera for contact and remote PPG. For contact PPG the sensor is mounted directly on the subjects body. The pulse wave is calculated as the mean amplitude intensity of all pixels. For remote PPG the sensor is mounted to measure the subjects face. The pulse wave cannot be found in every part of exposed skin. Therefore, the part of the skin with the clearest signal is localised and the pulse wave is recovered from there, by means of passband filtering and blind source separation. Our results show that contact PPG on a ToF camera has high accuracy and highly correlates with a commercial IR pulse oximetry device, as well as with an ECG grade chest belt. For remote PPG our method shows correlation with the ToF contact PPG signal.

Original languageEnglish
Title of host publicationProceedings - 21st Euromicro Conference on Digital System Design, DSD 2018
PublisherInstitute of Electrical and Electronics Engineers
Number of pages9
ISBN (Electronic)9781538673768
Publication statusPublished - 12 Oct 2018
Event21st Euromicro Conference on Digital System Design, DSD 2018 - Prague, Czech Republic
Duration: 29 Aug 201831 Aug 2018


Conference21st Euromicro Conference on Digital System Design, DSD 2018
Abbreviated titleDSD 2018
Country/TerritoryCzech Republic


  • Contact
  • Heart beat
  • Infrared
  • Photoplethysmography
  • PPG
  • Pulse
  • Remote
  • RPPG
  • Time-of-Flight
  • ToF

ASJC Scopus subject areas

  • Hardware and Architecture


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