Analysis of sound signal of five internal organs based on wavelet packet

Author(s):  
Jianjun Yan ◽  
Siyuan Mao ◽  
Chunming Xia ◽  
Chao Wang ◽  
Yiqin Wang ◽  
...  
Author(s):  
Jianjun Yan ◽  
Siyuan Mao ◽  
Chunming Xia ◽  
Qingwei Shen ◽  
Yiqin Wang ◽  
...  

2011 ◽  
Vol 1 ◽  
pp. 252-256 ◽  
Author(s):  
Guo Hua Zhang ◽  
Zhong Fan Yuan ◽  
Shi Xuan Liu

In order to extract pathological features of heart sound signal accurately, an algorithm for extracting the sub-band energy is developed based on the wavelet packet analysis. Through the spectrum analysis of heart sound signal, the sym7 wavelet, with high energy concentration and good time localization, is taken as the mother function, and the best wavelet packet basis of heart sound signal is picked out. Then, various heart sound signals are decomposed into four levels and the wavelet packet coefficients of the best basis are obtained. According to the equal-value relation between wavelet packet coefficients and signal energy in time domain, the normalized sub-band energy of the best basis is extracted as the feature vector. The mean of class separability measure is 3.049, which indicates that the algorithm is effective for feature extraction of heart sound signal.


2011 ◽  
Vol 317-319 ◽  
pp. 1211-1214 ◽  
Author(s):  
Guo Hua Zhang ◽  
Shi Xuan Liu

In order to extract pathological features of heart sound signal accurately, an algorithm for extracting the sub-band energy is developed based on the wavelet packet. The db6 wavelet is taken as the mother function, and the best wavelet packet basis of heart sound signal is picked out. Then, various heart sound signals are decomposed into four levels and the wavelet packet coefficients of the best basis are obtained. According to the equal-value relation between wavelet packet coefficients and signal energy in time domain, the normalized sub-band energy of the best basis is extracted as the feature vector. Based on BP network, seven identification models for seven kinds of heart sound were trained separately. Then, these models were tested by using 70 heart sounds, and the mean of identification accuracy is 72.9%.


Author(s):  
Weihai Sun ◽  
Lemei Han

Machine fault detection has great practical significance. Compared with the detection method that requires external sensors, the detection of machine fault by sound signal does not need to destroy its structure. The current popular audio-based fault detection often needs a lot of learning data and complex learning process, and needs the support of known fault database. The fault detection method based on audio proposed in this paper only needs to ensure that the machine works normally in the first second. Through the correlation coefficient calculation, energy analysis, EMD and other methods to carry out time-frequency analysis of the subsequent collected sound signals, we can detect whether the machine has fault.


2013 ◽  
Vol 61 (3) ◽  
pp. 613-621 ◽  
Author(s):  
W. Barnat

Abstract The article presents an approach to modeling the internal membrane pressure wave inside a sealed structure. During an explosion near a vehicle when a pressure wave reaches a hull, a pressure wave inside arises due to the hull’s bottom and the deformation of sides. They act like the piston - membrane. This membrane transfers the pressure impulse into the vehicle’s interior. A pressure increase causes the damage of internal organs or even death of occupants. In case of an armor penetration the pressure increase may be even larger. One of basic methods to protect a crew is to open hatches. However, such a method cannot be used in a contaminated area.


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