Blood Volume Pulse peak detector with a double adaptive threshold

Blood Volume Pulse (BVP) signal processing is a method to access heart rate and other cardiovascular parameters. In this work we developed an algorithm that detects the cardiac systole from the BVP signal with high accuracy. The implemented algorithm consists of a Slope Sum Function (SSF), an adaptive threshold strategy and a backsearch routine which works as a double adaptive threshold to enhance the sensitivity of the systole detection. In order to evaluate the performance of our algorithm we synchronously acquired BVP and eletrocardiogram (ECG) signals from a group of nineteen volunteers. The QRS complexes were annotated in the ECG signals and used as reference to detect false positives and false negatives in BVP detected systoles. The algorithm detected 99.94% of the 20 210 BVP systoles evident.