Data compression technique for high resolution wireless photoplethysmograph recording system

Multi-site photoplethysmography is an optoelectronic technique that measures changes in blood volume associated with cardiac contraction. Photoplethysmogram (PPG) recording enables researchers to study the vascular and hemodynamic properties of human subjects. Currently, there is no commercial system available in the market to perform multi-channel PPG recording. The measurements can be obtained from fingertips, ear lobes and toes due to their low absorption and high degree of vasculature. The main objective of this project is to develop a suitable data compression algorithm for two-channel simultaneous high resolution wireless PPG recording system. MATLAB software was used during the algorithm development phase to ensure the rapid prototyping. The result showed that delta modulation (DM) is able to compress PPG signals with a compression ratio (CR) up to 16 with an PRMSE of 3.92×10^-4. This system is expected to be a portable, wearable and battery operated device for clinical applications.