STATISTICAL WAVELET BASED ADAPTIVE NOISE FILTERING TECHNIQUE FOR MRI MODALITY

2018 ◽  
Vol 4 (4) ◽  
pp. 21
Author(s):  
ANJANAPPA C. ◽  
SHESHADRI H. S. ◽  
◽  
Keyword(s):  
Noise Filtering ◽  
Filtering Technique ◽  
Adaptive Noise

A Biophysical Model of Adaptive Noise Filtering in the Shark Brain

2014 ◽  
Vol 76 (2) ◽  
pp. 455-475 ◽  
Author(s):  
Peter Bratby ◽  
John Montgomery ◽  
James Sneyd
Keyword(s):  
Biophysical Model ◽  
Noise Filtering ◽  
Adaptive Noise

Noise filtering techniques for Lamb waves in structural health monitoring

2018 ◽  
Vol 14 (4) ◽  
pp. 676-694
Author(s):  
Ambuj Sharma ◽  
Sandeep Kumar ◽  
Amit Tyagi
Keyword(s):  
Crack Detection ◽  
Lamb Waves ◽  
Random Noise ◽  
Matched Filtering ◽  
Noise Filtering ◽  
Content Type ◽  
Time Frequency ◽  
Structural Health ◽  
Filtering Technique ◽  
Filtering Techniques

Purpose The real challenges in online crack detection testing based on guided waves are random noise as well as narrow-band coherent noise; and to achieve efficient structural health assessment methodology, magnificent extraction of noise and analysis of the signals are essential. The purpose of this paper is to provide optimal noise filtering technique for Lamb waves in the diagnosis of structural singularities. Design/methodology/approach Filtration of time-frequency information of guided elastic waves through the noisy signal is investigated in the present analysis using matched filtering technique which “sniffs” the signal buried in noise and most favorable mother wavelet based denoising methods. The optimal wavelet function is selected using Shannon’s entropy criterion and verified by the analysis of root mean square error of the filtered signal. Findings Wavelet matched filter method, a newly developed filtering technique in this work and which is a combination of the wavelet transform and matched filtering method, significantly improves the accuracy of the filtered signal and identifies relatively small damage, especially in enormously noisy data. A comparative study is also performed using the statistical tool to know acceptability and practicability of filtered signals for guided wave application. Practical implications The proposed filtering techniques can be utilized in online monitoring of civil and mechanical structures. The algorithm of the method is easy to implement and found to be successful in accurately detecting damage. Originality/value Although many techniques have been developed over the past several years to suppress random noise in Lamb wave signal but filtration of interferences of wave modes and boundary reflection is not in a much matured stage and thus needs further investigation. The present study contains detailed information about various noise filtering methods, newly developed filtration technique and their efficacy in handling the above mentioned issues.

A Spur-and-Phase-Noise-Filtering Technique for Inductor-Less Fractional-N Injection-Locked PLLs

2017 ◽  
Vol 52 (8) ◽  
pp. 2128-2140 ◽  
Author(s):  
Alvin Li ◽  
Yue Chao ◽  
Xuan Chen ◽  
Liang Wu ◽  
Howard C. Luong
Keyword(s):  
Phase Noise ◽  
Noise Filtering ◽  
Filtering Technique
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