IIR Based Digital Filter Design for Denoising the Photoplethysmography Signal

Photoplethysmography is a bioelectrical signal obtained from regions where the body's capillaries are dense, providing information about flowing blood volume. PPG signals contain a lot of information about the physiological and biological state of the person and are obtained with a lot of noise. In this study, Butterworth, Chebyshev Type I, Chebyshev Type II and Elliptic digital filters with Infinite Impulse Response were used to purify the PPG signal from noise. Performance analyzes were made with different values of filter parameters for each filter and the results were compared. As statistical parameters in performance analysis, Mean Square Error, Mean Absolute Error, Signal to Noise Ratio, Peak Signal to Noise Ratio and Cross Correlation criteria were used. According to the performance analysis results, a system in which the optimum filter parameters and filter type are determined for filtering the PPG signal is proposed.