determination of morphologically characteristic pcg segments from spectrogram image

The three-dimensional presentation of phonocardiac signal, simultaneously considering time, amplitude and frequency, allows the determination of morphological characteristic segments in phonocardiogram (PCG), both in short and long sequences. For this purpose, the STFT (Short-Time Fourier Transform) spectrogram images were used. By applying some methods known from image processing it is possible to recognize and extract basic heart sounds and murmurs from such time-frequency images. The method is tested over several characteristic test phonocardiac signals.