Fig. 4From: Camera-based photoplethysmography in an intraoperative settingReliability metrics of the ROI selection process. a Number of segments (NoS) per patient in which single ROIs were absent. b NoS in which the ROI detector had to be re-executed. c NoS in which the standard deviation of the mean ROI intensity exceeded 50 (see “Implementation and framework” section). Each boxplot depicts 41 patient-related valuesBack to article page