 | Gust N. Verbesserung der Signalauswertung für die Ultraschallmikroskopie = Improvement of signal analysis for the ultrasonic microscopy. - Dresden: TUDpress, 2011. - xiv, 102 p.: ill., graph. - (Dresdner Beiträge zur zerstörungsfreien Prüftechnik / Hrsg. von K.-J.Wolter, N.Meyendoff, H.Heuer; Bd.2). - ISBN 978-3-942710-22
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Kurzfassung ..................................................... V
Abstract ..................................................... VIII
List ob abbreviations ........................................ XIII
1 Introduction ................................................. 1
1.1 Motivation .............................................. 2
1.2 System theoretical description .......................... 3
1.3 Structure of the thesis ................................. 6
2 Sound field .................................................. 8
2.1 Sound field measurement ................................. 8
2.2 Sound field modeling ................................... 11
2.2.1 Reflection and transmission coefficients ........ 11
2.2.2 Sound field modeling with plane waves ........... 13
2.2.3 Generalized sound field position ................ 19
2.3 Receiving transducer signal ............................ 20
2.3.1 Calculation of the transducer signal from the
sound field ..................................... 20
2.3.2 Received signal amplitude ....................... 21
2.3.3 Measurement of reference signals ................ 24
3 Ultrasonic Simulation ....................................... 27
3.1 State of the art ....................................... 27
3.2 Simulation approach .................................... 28
3.2.1 Sound field measurement based simulation ........ 28
3.2.2 Reference signal based simulation ............... 30
3.3 Determination of the impulse response .................. 31
3.3.1 1D ray-trace algorithm .......................... 31
3.3.2 2D ray-trace algorithm .......................... 33
3.3.3 Complexity reduction - optimizations ............ 35
4 Deconvolution - Determination of reflection parameters ...... 38
4.1 State of the art ....................................... 39
4.1.1 Decomposition techniques ........................ 39
4.1.2 Deconvolution ................................... 41
4.2 Analytic signal investigations for deconvolution ....... 42
4.3 Single reference pulse deconvolution ................... 44
4.4 Multi-pulse deconvolution .............................. 47
4.4.1 Homogeneous multi-pulse deconvolution ........... 48
4.4.2 Multi-pulse deconvolution with simulated GSP
profile ......................................... 49
5 Reconstruction .............................................. 50
5.1 State of the art ....................................... 50
5.2 Reconstruction approach ................................ 51
5.3 Direct material parameter estimation ................... 52
5.3.1 Sound velocities and layer thickness ............ 52
5.3.2 Density, elastic modules and acoustic
attenuation ..................................... 54
5.4 Iterative material parameter determination of
a single layer ......................................... 56
5.5 Reconstruction of complex specimens .................... 60
5.5.1 Material characterization of multiple layers .... 60
5.5.2 Iterative simulation parameter optimization
with correlation ................................ 62
5.5.3 Pattern recognition reconstruction of
specimens with known base structure ............. 66
6 Applications and results .................................... 71
6.1 Analysis of stacked components ......................... 71
6.2 Time-of-flight and material analysis ................... 74
7 Conclusions and perspectives ................................ 78
References .................................................. 82
Figures ........................................................ 86
Tables ......................................................... 88
Appendix ....................................................... 89
Acknowledgments ............................................... 100
Danksagung .................................................... 101
Curriculum vitae .............................................. 102
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