Analysis of Reflectance Photoplethysmograph Sensors
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 32845
Analysis of Reflectance Photoplethysmograph Sensors

Authors: Fu-Hsuan Huang, Po-Jung Yuan, Kang-Ping Lin, Hen-Hong Chang, Cheng-Lun Tsai


Photoplethysmography is a simple measurement of the variation in blood volume in tissue. It detects the pulse signal of heart beat as well as the low frequency signal of vasoconstriction and vasodilation. The transmission type measurement is limited to only a few specific positions for example the index finger that have a short path length for light. The reflectance type measurement can be conveniently applied on most parts of the body surface. This study analyzed the factors that determine the quality of reflectance photoplethysmograph signal including the emitter-detector distance, wavelength, light intensity, and optical properties of skin tissue. Light emitting diodes (LEDs) with four different visible wavelengths were used as the light emitters. A phototransistor was used as the light detector. A micro translation stage adjusts the emitter-detector distance from 2 mm to 15 mm. The reflective photoplethysmograph signals were measured on different sites. The optimal emitter-detector distance was chosen to have a large dynamic range for low frequency drifting without signal saturation and a high perfusion index. Among these four wavelengths, a yellowish green (571nm) light with a proper emitter-detection distance of 2mm is the most suitable for obtaining a steady and reliable reflectance photoplethysmograph signal

Keywords: Reflectance photoplethysmograph, Perfusion index, Signal-to-noise ratio

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2127


[1] Allen J, Frame JR and Murry A, Microvascular blood flow and skin temperature changes in the fingers following a deep inspiratory gasp, Physiol Meas, 23:365-373, 2002.
[2] Allen J, Photoplethysmography and its application in clinical physiological measurement, Physiol Meas, 28, R1-R39, 2007.
[3] Anderson RR and. Parrish JA, The optics of human skin, J Invest Dermatol, 77(1):13-19, 1981.
[4] Soehnge H, Ouhtit A and Ananthaswamy HN, Mechanisms of Introduction of Skin Cancer by UV radiation, Frontiers in Bioscience, 2:d538-551, 1977.
[5] Reuss JL and Siker D, The pulse in reflectance pulse oximetry: Modeling and experimental studies, J Clin. Monit. Comput, 18(4):289-299, 2004.
[6] Thanassis P, Effects of fiber-optic probe design and probe-to-target distance on diffuse reflectance measurements of turbid media: an experimental and computational study at 337 nm, Appl Opt, 43:2846-2860, 2004.
[7] Mendelson Y and Ochs B, Noninvasive Pulse Oximetry Utilizing Skin Reflectance Photoplethysmography, IEEE Trans Biomed Eng, 35:798-805, 1988.