A Fast Compression Method of Photoplethysmogram Signal

The aim of this study is to store more raw photoplethysmogram(PPG) signals for analysis in limited storage space, due to the problem of mass data gathering when the wearable device detects dynamic PPG signals for a long time. Hence this study proposes a method that includes PPG data sampling and compression, PPG data decompression and analysis. Firstly, data is sampled in a sliding window and noise in the signal is suppressed by an improved adaptive filtering method; Then, the preprocessed data in the current data buffer is compressed, and the compressed data is encoded and sent; next, the compressed data is received and stored, and the decoded and recovered data is analysed. Using the simulated PPG signal and the measured PPG signal as the experimental data, the results show that compared with the existing method, the proposed method can effectively improve the compression ratio within the acceptable error range between the restored data and the original data, and the compressed data can be used for heart rate extraction from pulse signals. The proposed method is expected to be used in smart wearable devices with high real-time requirements such as wristbands and watches.