An atmospheric noise suppression method based on synchrosqueezed wavelet transform

Author(s):  
Huan Hao ◽  
Huali Wang ◽  
Liang Chen
2014 ◽  
Vol 989-994 ◽  
pp. 3726-3729
Author(s):  
Xiu Fang Liu

The telemetry signal is often interfered with impulse noise, which results in difficulty in time domain and frequency domain analysis results. Hereby a new impulse noise suppression method based on wavelet transform and median filtering technique was proposed. The received signal is decomposed into detailed components and approximate components, and then the median filtering is carried on the wavelet decomposition components with vary filtering window size according to the wavelet transform scale respectively. This method can suppress the impulse noise effectively and keep the detail information of the signal from the loss at the same time. The simulation and experimental results prove the effectiveness of the method.


Author(s):  
Takafumi Kinoshita ◽  
Koichi Fujiwara ◽  
Manabu Kano ◽  
Keiko Ogawa ◽  
Yukiyoshi Sumi ◽  
...  

Author(s):  
Wenchao Du ◽  
Hu Chen ◽  
Hongyu Yang ◽  
Yi Zhang

AbstractGenerative adversarial network (GAN) has been applied for low-dose CT images to predict normal-dose CT images. However, the undesired artifacts and details bring uncertainty to the clinical diagnosis. In order to improve the visual quality while suppressing the noise, in this paper, we mainly studied the two key components of deep learning based low-dose CT (LDCT) restoration models—network architecture and adversarial loss, and proposed a disentangled noise suppression method based on GAN (DNSGAN) for LDCT. Specifically, a generator network, which contains the noise suppression and structure recovery modules, is proposed. Furthermore, a multi-scaled relativistic adversarial loss is introduced to preserve the finer structures of generated images. Experiments on simulated and real LDCT datasets show that the proposed method can effectively remove noise while recovering finer details and provide better visual perception than other state-of-the-art methods.


Author(s):  
Lakshmi M Hari ◽  
Gopinath Venugopal ◽  
Swaminathan Ramakrishnan

In this study, the dynamic contractions and the associated fatigue condition in biceps brachii muscle are analysed using Synchrosqueezed Wavelet Transform (SST) and singular value features of surface Electromyography (sEMG) signals. For this, the recorded signals are decomposed into time-frequency matrix using SST. Two analytic functions namely Morlet and Bump wavelets are utilised for the analysis. Singular Value Decomposition method is applied to this time-frequency matrix to derive the features such as Maximum Singular Value (MSV), Singular Value Entropy (SVEn) and Singular Value Energy (SVEr). The results show that both these wavelets are able to characterise nonstationary variations in sEMG signals during dynamic fatiguing contractions. Increase in values of MSV and SVEr with the progression of fatigue denotes the presence of nonstationarity in the sEMG signals. The lower values of SVEn with the progression of fatigue indicate the randomness in the signal. Thus, it appears that the proposed approach could be used to characterise dynamic muscle contractions under varied neuromuscular conditions.


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