Title :
Bayesian classification of ultrasound signals using wavelet coefficients
Author :
Meyer, Edward ; Tuthill, Theresa
Author_Institution :
Dayton Univ., OH, USA
Abstract :
Ultrasound is a common tool in the nondestructive evaluation of composite material integrity. Echoes from high frequency (5-10 MHz) sound waves vary with subsurface flaws and delaminations. To improve detection of internal defects in composite materials, a linear Bayes classification is applied to the wavelet transform coefficients of ultrasound scan lines. Using a Daubechies basis, wavelet transforms are taken of the ultrasound signals. A subset of the coefficients is then used as features for the classifier. A forward sequential feature selection (FSFS) algorithm was used to determine the optimal features. The training set was comprised of scanned signals from both damaged and undamaged samples. Performance statistics for classification of damaged materials were calculated using a separate set of test samples. Application of a shift-invariant wavelet transform removed some of the variability of the wavelet coefficients and improved the classification
Keywords :
Bayes methods; acoustic signal detection; acoustic signal processing; composite materials; delamination; feature extraction; flaw detection; pattern classification; ultrasonic materials testing; wavelet transforms; Bayesian classification; Daubechies basis; Echoes; classification; composite material integrity; composite materials; delaminations; detection of internal defects; forward sequential feature selection algorithm; linear Bayes classification; nondestructive evaluation; optimal features; shift-invariant wavelet transform; sound waves; statistics; subsurface flaws; ultrasound scan lines; variability; wavelet coefficients; wavelet transform coefficients; Bayesian methods; Composite materials; Delamination; Frequency; Materials testing; State feedback; Statistical analysis; Ultrasonic imaging; Wavelet coefficients; Wavelet transforms;
Conference_Titel :
Aerospace and Electronics Conference, 1995. NAECON 1995., Proceedings of the IEEE 1995 National
Conference_Location :
Dayton, OH
Print_ISBN :
0-7803-2666-0
DOI :
10.1109/NAECON.1995.521945