Border Extension in the Wavelet Analysis of Lung Sounds

Wavelet Transform (WT) is normally used in lung sounds signal processing and showed the best result. However, the effect of different ways of signal extensions on this partic- ular application has not been previously studied. The proper use and interpretation of the border extension plays a signifi- cant role in the lung sounds signal processing. In this paper a study of the Discrete Wavelet Transform (DWT) and of the sig- nal extension methods is performed. An experiment comparing different methods and results is presented. The differences be- tween the application of different border extension methods are showed and discussed.