Imaging in the presence of grain noise using the decomposition of the time reversal operator

被引:36
作者
Kerbrat, E [1 ]
Prada, C [1 ]
Cassereau, D [1 ]
Fink, M [1 ]
机构
[1] Univ Paris 07, ESPCI, Lab Ondes & Acoust, CNRS,UMR 7587, F-75005 Paris, France
关键词
D O I
10.1121/1.1548156
中图分类号
O42 [声学];
学科分类号
070206 ; 082403 ;
摘要
In this paper, we are interested in detecting and imaging defects in samples of cylindrical geometry with large speckle noise due to the microstructure.. The time reversal process is an appropriate technique for detecting flaws in such heterogeneous media as titanium billets. Furthermore, time reversal can be iterated to select the defect with the, strongest reflectivity and to reduce the contribution of speckle noise. The DORT (the French acronym for Decomposition of the Time Reversal Operator) method derives from the mathematical analysis of the time reversal, process. This detection technique allows the determination of a set of signals to be applied to the transducers in order to focus on each defect separately. In this paper, we compare three immersion techniques on a titanium sample, standard transmit/receive focusing, the time reversal mirror (TRM), and the DORT method. We compare the sensitivity of these three techniques, especially the sensitivity to a poor alignment of the array with the front face of the sample. Then,we show how images of the, sample can be obtained with the TRM and the DORT method using backpropagation algorithm. (C) 2003 Acoustical Society of America.
引用
收藏
页码:1230 / 1240
页数:11
相关论文
共 19 条
[1]   Imaging and time reversal in random media [J].
Borcea, L ;
Papanicolaou, G ;
Tsogka, C ;
Berryman, J .
INVERSE PROBLEMS, 2002, 18 (05) :1247-1279
[2]  
CASSEREAU D, 1997, THESIS PARIS
[3]   TIME-REVERSAL PROCESSING IN ULTRASONIC NONDESTRUCTIVE TESTING [J].
CHAKROUN, N ;
FINK, MA ;
WU, F .
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, 1995, 42 (06) :1087-1098
[4]  
CHATILLON S, 2000, REV PROGR QNDE, V19, P1095
[5]   TIME-REVERSAL OF ULTRASONIC FIELDS .1. BASIC PRINCIPLES [J].
FINK, M .
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, 1992, 39 (05) :555-566
[6]  
FINK M, 1989, IEEE 1989 ULTRASONICS SYMPOSIUM : PROCEEDINGS, VOLS 1 AND 2, P681, DOI 10.1109/ULTSYM.1989.67072
[7]  
HOWARD PJ, 1996, IEEE ULTRASON S P, V1, P727
[8]   SYNTHETIC-APERTURE IMAGING FOR SMALL-SCALE SYSTEMS [J].
KARAMAN, M ;
LI, PC ;
ODONNELL, M .
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, 1995, 42 (03) :429-442
[9]  
KERBRAT E, 2000, REV PROG QNDE, P934
[10]  
Li AX, 2001, REV PROG Q, V557, P1322