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Journal of Biomedical Optics • Open Access

Use of ambient light in remote photoplethysmographic systems: comparison between a high-performance camera and a low-cost webcam
Author(s): Yu Sun; Vicente Azorin-Peris; Roy Kalawsky; Sijung Hu; Charlotte Papin; Stephen E. Greenwald

Paper Abstract

Imaging photoplethysmography (PPG) is able to capture useful physiological data remotely from a wide range of anatomical locations. Recent imaging PPG studies have concentrated on two broad research directions involving either high-performance cameras and or webcam-based systems. However, little has been reported about the difference between these two techniques, particularly in terms of their performance under illumination with ambient light. We explore these two imaging PPG approaches through the simultaneous measurement of the cardiac pulse acquired from the face of 10 male subjects and the spectral characteristics of ambient light. Measurements are made before and after a period of cycling exercise. The physiological pulse waves extracted from both imaging PPG systems using the smoothed pseudo-Wigner-Ville distribution yield functional characteristics comparable to those acquired using gold standard contact PPG sensors. The influence of ambient light intensity on the physiological information is considered, where results reveal an independent relationship between the ambient light intensity and the normalized plethysmographic signals. This provides further support for imaging PPG as a means for practical noncontact physiological assessment with clear applications in several domains, including telemedicine and homecare.

Paper Details

Date Published: 23 March 2012
PDF: 11 pages
J. Biomed. Opt. 17(3) 037005 doi: 10.1117/1.JBO.17.3.037005
Published in: Journal of Biomedical Optics Volume 17, Issue 3
Show Author Affiliations
Yu Sun, Loughborough Univ. (United Kingdom)
Vicente Azorin-Peris, Loughborough Univ. (United Kingdom)
Roy Kalawsky, Loughborough Univ. (United Kingdom)
Sijung Hu, Loughborough Univ. (United Kingdom)
Charlotte Papin, Univ. Paris-Sud 11 (France)
Stephen E. Greenwald, Barts and The London School of Medicine and Dentistry (United Kingdom)


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