Wavelets and Their Application to Digital Signal Processing in Ultrasonic NDE

Visualisation of fouling during microfiltration of natural brown water by using wavelets of ultrasonic spectra

“…For complicated samples, FT treats the signal as a continuous function, and the arrival time and local magnitude of peaks in the transient signals are difficult to analyse [38], yet for proper interaction and interpretation, a signal should be accurately presented in the time and frequency-domain simultaneously. "Wavelet transform (WT)", that shows a time-frequency-amplitude analysis of transient ultrasonic signals [39][40][41][42][43], is a more recent approach to measure fouling. Wavelets are mathematical functions, Fourier transforms, of short duration (multiple slices of a curve) that divide the amplitude-time data into closely adjacent (narrow slices) frequency components, and thus one can identify any frequency component with its location in time, so ensuring a true FT rendition of the original signal [38,44].…”

Applications of Statistical Methods to Nondestructive Evaluation

“…'he frequency-For nonstationary signals, the Kalman filter is widely the scattering used and several NDE researchers have been exploring the use of wavelet methods (e.g., see Giiler et al 1994;Patter-,essing are (a) son, DeFacio, Neal, and Thompson 1993). ero A(w)] and r(t) or A(w).…”

<title>Wavelet inversions of elastic wave data for nondestructive evaluation</title>

“…Nondestruction evaluation, NDE [1][2][3][4][5][6][7][8][9][10], is an important part of the national economy for several reasons: it can improve health and safety decisions including medical imaging modalities, and the inspection of airplanes, radars, bridges, roads, etc. ; it can help to increase reliability and productivity in manufacturing; and it can assist in the development of new products for information storage and transmission and for communications, e.g.…”