Comparison between short time Fourier and wavelet transform for feature extraction of heart sound

Presents the application of the wavelet transform analysis method to the phonocardiogram (PCG) signal. Heart sound is a highly nonstationary signal. So in the analysis of heart sound it is important to study the frequency and time information. To investigate the exact features of heart sound we adopt Short-Time Fourier Transform (STFT) and Wavelet Transform (WT) as a time-frequency representation. As a result, it is found that the first sound in the PCG signal and the two components of the second sound are inaccurately detected. On the other hand, it is found that the wavelet transform is capable of detecting the two components, the aortic valve component A2 and pulmonary valve component P2, of the second sound S2 in a normal PCG signal. Furthermore, the wavelet transform provides more features and characteristics of the PCG signals that will help the physician to obtain qualitative and quantitative measurements of the heart sound.