Reduction of motion artifact of photoplethysmogram signal based on its frequency distribution

In this paper, we proposed and evaluated signal processing algorithms which could efficiently reduce motion artifacts contained in the photoplethysmogram (PPG) signal. Time-domain PPG signal was analyzed to find frequency distribution of the fundamental and harmonic components caused by the arterial blood flow and motion artifact. A new artificial PPG signal could be reconstructed by using only the fundamental and harmonic components caused by the arterial blood flow. This motion artifacts reduced signal was further analyzed in time domain to obtain its AC components by applying peak detection algorithm. The algorithms proposed in this study showed correct saturation of peripheral oxygen (SpO₂) values for the PPG signal in which the fundamental and harmonic components were not overlapped.