Motion Artifact Reduction and Data Compression of Photoplethysmo-graphic Signals utilizing Cycle by Cycle Fourier Series Analysis

Artifact-free clean photoplethysmographic (PPG) signals obtained at red and infrared (IR) wavelengths are required for the estimation of the level of oxygen saturation (SpO₂) in arterial blood of a patient. Movement of a patient corrupts a PPG signal with motion artifacts and introduces large errors in the computation of SpO₂- A novel method to remove motion artifacts from corrupted PPG signals by applying Fourier series analysis on a cycle by cycle basis is presented in this paper. Over and above artifact reduction, the proposed method also provides data compression. Experimental results indicate that the proposed method is insensitive to heart rate variation, introduces negligible error in the processed PPG signals due to the additional processing, preserves all the morphological features of the PPG, provides 35 dB reduction in motion artifact and achieves a data compression factor of 12.