Reduction of Dispersive Wave Modes in Guided Wave Testing using Split-Spectrum Processing

Split-Spectrum Signal Processing (SSP) technique presents in this paper with application to Ultrasonic Guided Wave (UGW) testing. The problem of background/coherent noise due to presence of Dispersive Wave Modes (DWM) in the context of ultrasonic scattering is addressed and a novel solution is proposed for reduction of the effects of DWM in the received signal by utilizing the SSP technique. The proposed technique investigates the sensitivity of SSP application to the filter bank parameter values such as number of filters, filter bandwidth, and filter overlap. Therefore, as a result the optimum values are introduced that significantly improves the Signal-to-noise ratio (SNR). The proposed method has been compared with conventional approaches and tested with different type of recombination techniques for a synthesized signal of 6 inch pipe. The Polarity Thresholding (PT) algorithm was found to give the best result and substantially improves the SNR performance by an average of 10 dB

Keywords:

Split-Spectrum Processing , SNR , Ultrasonic Guided Waves , Signal Processing