VLSI Wavelet Based Denoising of PPG Signal

Abstract

Wavelet denoising represents a common preprocessing step for several biomedical applications exposing low SNR. These applica- tions require real time processing along with minimization of power and area, only custom VLSI implementations can be adopted for this fulfillment. In this paper, Photoplethysmography (PPG) signal is used as a biomedical signal as an example. PPG is a non-invasive method in which relative blood volume changes in the blood close to skin is measured. The “pulse waveform” never underwent intensive investigation. Active investigation efforts are opening to reveal its effectiveness beyond oxygen saturation and determination of heart rate. With the introduction of pulse oximeter, this is one of the important waveforms that are normally dis- played in the clinical settings nowadays. But, the acquired PPG signal using PPG sensors are usually corrupted with different kinds of interference like Motion Artifacts, Power Line Noise, etc. We consider Power Line Noise for the performance evaluation of VLSI Wavelet based denoising of PPG signal. Different kinds of Wavelets such as db4, Coif1, Haar for denoising. Also, standard deviation and mean absolute deviation are used as evaluation criteria. Xilinx System Generator for DSP is exploited for the design of the architecture and simulation of proposed denoising method.