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Noise Smoothing for Structural Vibration Test Signals Using an Improved Wavelet Thresholding Technique
Faculty of Infrastructure Engineering, State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116023, China
Shanghai Municipal Engineering Design Institute (group) Co. Ltd., Shanghai 200092, China
* Author to whom correspondence should be addressed.
Received: 11 June 2012; in revised form: 6 August 2012 / Accepted: 6 August 2012 / Published: 10 August 2012
Abstract: In structural vibration tests, one of the main factors which disturb the reliability and accuracy of the results are the noise signals encountered. To overcome this deficiency, this paper presents a discrete wavelet transform (DWT) approach to denoise the measured signals. The denoising performance of DWT is discussed by several processing parameters, including the type of wavelet, decomposition level, thresholding method, and threshold selection rules. To overcome the disadvantages of the traditional hard- and soft-thresholding methods, an improved thresholding technique called the sigmoid function-based thresholding scheme is presented. The procedure is validated by using four benchmarks signals with three degrees of degradation as well as a real measured signal obtained from a three-story reinforced concrete scale model shaking table experiment. The performance of the proposed method is evaluated by computing the signal-to-noise ratio (SNR) and the root-mean-square error (RMSE) after denoising. Results reveal that the proposed method offers superior performance than the traditional methods no matter whether the signals have heavy or light noises embedded.
Keywords: vibration testing; wavelet transform (WT); denoise; wavelet thresholding; sigmoid function
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Yi, T.-H.; Li, H.-N.; Zhao, X.-Y. Noise Smoothing for Structural Vibration Test Signals Using an Improved Wavelet Thresholding Technique. Sensors 2012, 12, 11205-11220.
Yi T-H, Li H-N, Zhao X-Y. Noise Smoothing for Structural Vibration Test Signals Using an Improved Wavelet Thresholding Technique. Sensors. 2012; 12(8):11205-11220.
Yi, Ting-Hua; Li, Hong-Nan; Zhao, Xiao-Yan. 2012. "Noise Smoothing for Structural Vibration Test Signals Using an Improved Wavelet Thresholding Technique." Sensors 12, no. 8: 11205-11220.