Fig. 4: Working principle of PPG195.
From: Emerging sensing and modeling technologies for wearable and cuffless blood pressure monitoring
a Reflective mode. b transmitting mode. c example of PPG signal. d Reflective mode epidermal and transmissive mode flexible hybrid organic/inorganic NIR PPG for BP monitoring. Reprinted with permission from ref. 59. Copyright 2017 Wiley.
