The research and application of heart sound (HS) analysis for cardiovascular disease (CVD) diagnosis has attracted more attention recently. Unlike other relevant HS analysis research, such as HS detection/component segmentation, HS feature extraction/classification etc., the proposed research treats HS as a whole and focuses mainly on comparing the similarity of acoustical characteristics reflecting pathological condition between two HSs, one of which is HS under test and another is the HS with known CVD. The concrete procedure refers to alignment of the HS into sequence and evaluating the similarity index through complexity and similarity analysis. In accordance with specific characteristics of HS, several relevant technologies such as musical instrument digital interface (MIDI), binary coding, N-gram, Lempel-Ziv (L-Z) complexity as well as super-symmetric comparison distance (SCD) similarity metric etc. are researched to be adapted and cascaded to realize the aforementioned target successfully. The contribution lies in that the aligning schemes including binary and N-gram are thoroughly investigated and then testing results witnessing the superiority of using N-gram in proposed approach are presented. The success of such a novel approach would not only assign a the new life to the traditional auscultation CVD diagnosis, but also simplify CVD diagnosis greatly leading to extensive application of such an efficient non-invasive physical diagnostic method in e-home healthcare.
Fu, B. B., Fei, X. L., Sekar, B., & Dong, M. C. (2013). Research and Application of Heart Sound Alignment and Descriptor. Computers in Biology and Medicine, 20(3), 211-218. https://doi.org/10.1016/j.compbiomed.2012.11.002