BREATH SOUNDS - RECORDING AND CLASSIFICATION PROBLEMS

A physical and mathematical description of human breath sounds has bee n reviewed. The models concern the mechanisms of the generation and pr opagation of basic (bronchial and vesicular) sounds and additional (wh eezes and crepitation) respiratory sounds. It has been demonstrated th at breath sounds should be recorded in the body by accelerometer-type transducers, which react at vibratory velocities. The basic requiremen ts concerning the mass and size of these probes have been formulated. Using statistical hypothesis testing, we have synthesized optimal and adaptive algorithms for the classification of respiratory sounds. Thes e algorithms allow for the nonstationarity of these sounds. The adapti ve algorithm defines the proximity between the observed and the refere nce realizations of breath sounds as having been derived from their sp ectral and temporal characteristics. The principal procedures of adapt ive processing are spectral analysis, the averaging of spectral sample s over time and frequency intervals, and the stationarization of breat h sounds. The classification algorithms have been tested experimentall y in two groups of children: one healthy and one with bronchitis.