A Consideration on Optimal Non-linear Function to Separate Auscultation Sounds Using BSS

Conventionally, by mixed respiratory sound and heart sound in auscultation, appropriate diagnosis often prevented. In order to solve this problem, a method of separating respiratory sound and heart sound based on blind source separation (BSS) has been proposed. However, there is the problem that sufficient separation precision cannot be obtained. In the BSS method, it is necessary to use an optimal non-linear function for the signal distribution. However, there is no non-linear function corresponding to the distribution of respiratory sound and the distribution of heart sound. This was a factor that made it impossible to obtain a sufficient separation precision. Therefore, in this study, we propose three non-linear functions appropriately corresponding to super Gaussian distribution through sub-Gaussian distribution to uniform distribution. We evaluate the effectiveness of this method by computer simulation in section 3 and confirm its effectiveness.