Open AccessThe value of polarization in camera-based photoplethysmography
Author(s) -
Alexander Trumpp,
Philipp L. Bauer,
Stefan Rasche,
Hagen Malberg,
Sebastian Zaunseder
Publication year - 2017
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.8.002822
Subject(s) - photoplethysmogram , computer science , computer vision , image quality , artificial intelligence , polarization (electrochemistry) , signal processing , signal (programming language) , filter (signal processing) , optics , physics , telecommunications , radar , chemistry , image (mathematics) , programming language
Camera-based photoplethysmography (cbPPG) is a novel measuring technique that permits the remote acquisition of cardiovascular signals using video cameras. Research still lacks in fundamental studies to reach a deeper technical and physiological understanding. This work analyzes the employment of polarization filtration to (i) assess the gain for the signal quality and (ii) draw conclusions about the cbPPG signal's origin. We evaluated various forehead regions of 18 recordings with different color and filter settings. Our results prove that for an optimal illumination, the perpendicular filter setting provides a significant benefit. The outcome supports the theory that signals arise from blood volume changes. For lateral illumination, ballistocardiographic effects dominate the signal as polarization's impact vanishes.