Hybrid method for noise rejection from breath sound using transient artifact reduction algorithm and spectral subtraction.

OBJECTIVES: Computerized breath sound based diagnostic methods are one of the emerging technologies gaining popularity in terms of detecting respiratory disorders. However, the breath sound signal used in such automated systems used to be too noisy, which affects the quality of the diagnostic interpretations. To address this problem, the proposed work presents the new hybrid approach to reject the noises from breath sound.

METHODS: In this method, 80 chronic obstructive pulmonary disease (COPD), 75 asthmatics and 80 normal breath sounds were recorded from the participants of a hospital. Each of these breath sound data were decontaminated using hybrid method of Butterworth band-pass filter, transient artifact reduction algorithm and spectral subtraction algorithm. The study examined the algorithms noise rejection potential over each category of breath sound by estimating the noise rejection performance metrics, i.e., mean absolute error (MAE), mean square error (MSE), peak signal to noise ratio (PSNR), and signal to noise ratio (SNR).

RESULTS: Using this algorithm, the study obtained a high value of SNR of 70 dB and that of PSNR of 72 dB.

CONCLUSIONS: The study could definitely a suitable one to suppress noises and to produce noise free breath sound signal.