Blue as an Underrated Alternative to Green: Photoplethysmographic Heartbeat Intervals Estimation under Two Temperature Conditions
Open Access
- 21 June 2021
- Vol. 21 (12), 4241
- https://doi.org/10.3390/s21124241
Abstract
Since photoplethysmography (PPG) sensors are usually placed on open skin areas, temperature interference can be an issue. Currently, green light is the most widely used in the reflectance PPG for its relatively low artifact susceptibility. However, it has been known that hemoglobin absorption peaks at the blue part of the spectrum. Despite this fact, blue light has received little attention in the PPG field. Blue wavelengths are commonly used in phototherapy. Combining blue light-based treatments with simultaneous blue PPG acquisition could be potentially used in patients monitoring and studying the biological effects of light. Previous studies examining the PPG in blue light compared to other wavelengths employed photodetectors with inherently lower sensitivity to blue, thereby biasing the results. The present study assessed the accuracy of heartbeat intervals (HBIs) estimation from blue and green PPG signals, acquired under baseline and cold temperature conditions. Our PPG system is based on TCS3472 Color Sensor with equal sensitivity to both parts of the light spectrum to ensure unbiased comparison. The accuracy of the HBIs estimates, calculated with five characteristic points (PPG systolic peak, maximum of the first PPG derivative, maximum of the second PPG derivative, minimum of the second PPG derivative, and intersecting tangents) on both PPG signal types, was evaluated based on the electrocardiographic values. The statistical analyses demonstrated that in all cases, the HBIs estimation accuracy of blue PPG was nearly equivalent to the G PPG irrespective of the characteristic point and measurement condition. Therefore, blue PPG can be used for cardiovascular parameter acquisition. This paper is an extension of work originally presented at the 42nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society.Keywords
This publication has 23 references indexed in Scilit:
- Accuracy of heart rate variability estimation by photoplethysmography using an smartphone: Processing optimization and fiducial point selection2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
- A randomized controlled study for the treatment of acne vulgaris using high-intensity 414 nm solid state diode arraysJournal of Cosmetic and Laser Therapy, 2015
- Extraction of Heart Rate Variability from Smartphone PhotoplethysmogramsComputational and Mathematical Methods in Medicine, 2015
- The Effect of Light Conditions on Photoplethysmographic Image Acquisition Using a Commercial CameraIEEE Journal of Translational Engineering in Health and Medicine, 2014
- iPhone 4s Photoplethysmography: Which Light Color Yields the Most Accurate Heart Rate and Normalized Pulse Volume Using the iPhysioMeter Application in the Presence of Motion Artifact?PLOS ONE, 2014
- Comparison between red, green and blue light reflection photoplethysmography for heart rate monitoring during motion2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013
- Optical properties of the human skin / Optičke osobine ljudske kožeSerbian Journal of Dermatology and Venereology, 2010
- Photodynamic Therapy With Aminolevulinic Acid Topical Solution andVisible Blue Light in the Treatment of Multiple Actinic Keratoses of the Faceand ScalpArchives of Dermatology, 2004
- Phototherapy and the Photobiology of BilirubinSeminars in Liver Disease, 1988
- A New Biometrical Procedure for Testing the Equality of Measurements from Two Different Analytical Methods. Application of linear regression procedures for method comparison studies in Clinical Chemistry, Part Icclm, 1983