| 摘要 |
A device and a method for the auscultation of heart or lung sounds or similar acoustic signals generated by the internal organs of a body are described, based upon the acquisition of an auscultation signal including a useful signal superimposed on an ambient noise signal, and of an ambient noise signal nearby, and upon the rejection of the ambient noise signal component from the auscultation signal. The acquired signals are converted into digital electrical signals, and the target auscultation signal is obtained by subtraction of the ambient noise digital signal, filtered through a digital filter arrangement having an adaptive transfer function, from the digital auscultation signal. The filter coefficients of the adaptive digital filter arrangement are calculated according to the minimisation of the energy of the target auscultation signal, and more specifically according to the minimisation of an energy functional ¦ 2 defined as: ¦ 2 = ˆ‘ n = - M 0 S n 2 + ˆ‘ k = 0 N - 1 X 2 k
in which S(n) is the target auscultation signal and X(k) is the filter impulse response. |
