General ROI Selection Approach in rPPG for Accurate Heart Rate Estimation

Selecting the optimal region of interest (ROI) in remote photoplethysmography (rPPG) is crucial for capturing desired pulsatile information accurately. We propose a novel method to identify the best subject-dependent region by employing variable-size segmentation to meet minimum accuracy criteria for heart rate estimation. By selecting the intersection of these segments, we determine the subject-dependent optimal region. Finally, through geometrical transformations and the amalgamation of all subject-dependent regions, we derive the ultimate subject-independent ROI. Our findings indicate that the optimal region for extracting rPPG signals is an area on the forehead, encompassing the mid-nasal ridge within the supratrochlear vein passage. Additionally, heart rate estimation utilizing this specified region achieved accuracy rates above 98% across all cases, demonstrating the effectiveness of this region for rPPG estimation. Through our research, we aim to contribute to the ongoing development of precise and robust physiological measurements using rPPG technology.