[Retracted] Improvement of the Accuracy in the Identification of Coronary Artery Disease Combining Heart Sound Features

Figure 4

The segmentations of different S1’s Fourier spectrum. (a) Normal S1; (b) S1 of mitral stenosis; (c) S1 split; (d) S1 of CAD.

(a)

(b)

(c)

(d)