HHT based lung sound crackle detection and classification

Crackles are discontinuous adventitious lung sounds, characterized by waveforms with a rapid onset and short duration. Traditional approaches to detect and classify crackles are mainly from the morphological aspect, however, the sharp patterns of crackles in frequency domain were overlooked. In this paper we employ the innovative HHT method to detect and classify crackles. By detecting peaks in time-frequency distribution derived from HHT, segments are extracted, then, crackles can be identified and classified efficiently. Relevant theories, methods and experimental results are given in detail.