AGU-Vallen Wavelet

About wavelet transformation
A wavelet transform (WT) of an AE signal provides information which wave modes carry significant energy and where in a mode the energy as a function of frequency and time is to be found. Thereby a WT can communicate very useful information.

Contributors
AGU-Vallen Wavelet has been developed in collaboration between VallensSysteme GmbH and with Aoyama Gakuin University (AGU), Tokyo, Japan. The AGU group has pioneered in the research of wavelet analysis in the field of Acoustic Emission and Vallen has actively generated software tools.

The following is a list of persons, who have significantly contributed to the AGU-Vallen Wavelet program, as of 2010:

Prof. Mikio Takemoto, Aoyama Gakuin University (AGU), Tokyo, Japan
Head of Materials Science Laboratory, Aoyama Gakuin University (AGU)
Prof. Takemoto has guided the development of the AGU-wavelet from the first stage. Together with Prof. Ono (UCLA), Prof. Takemoto ignited the initial spark to start the development of AGU-Vallen Wavelet project.

Prof. Kanji Ono, University of California (UCLA), Los Angeles, USA
Prof. Ono has participated in wavelet research at AGU and facilitated a contact between AGU and Vallen. Prof. Ono is author of many AE and wavelet papers published or presented at international conferences. See also the literature references at the end of this page.

Prof. Yasuhisa Hayashi*, Shizuoka University, Shizuoka, Japan
Dr. Hideo Cho*, Tohoku University, Sendai, Japan
Dr. Hiroaki Suzuki*, Chiyoda Co., Kawasaki, Japan
Tetsuo Kinjo**, Ishikawajima-Harima Heavy Industries Co. Ltd.
* Former assistants of Materials Science Laboratory in AGU.
** Graduate of Graduate School, AGU.
Prof. Hayashi, Dr. Suzuki and Mr. Kinjo created the initial AGU-wavelet software for Acoustic Emission analysis. Prof. Hayashi and Dr. Cho demonstrated the usage of wavelet transform for determining the group velocity of elastic waves.

Prof. Yoshihiro Mizutani, Mechanical Engineering, Tokyo Institute of technology, Tokyo, Japan.
Dr. Mizutani completely upgraded the original AGU wavelet algorithm for arbitrary frequency analysis at AGU. His algorithm is implemented in the AGU-Vallen Wavelet program with kind permission of Dr. Mizutani and Prof. Takemoto.  He continuously provides advice regarding the AGU-Vallen wavelet.

Prof. Marvin A. Hamstad, National Institute of Standards and Technology (NIST), Boulder, Co USA and University of Denver, Co. USA
Prof. Hamstad is the very first scientific user of AGU-Vallen Wavelet. He accompanied the development of the program and contributed data samples created by finite element modeling (FEM) and an overview presentation about the use and value of wavelet transformation. This presentation together with FEM samples is included in the distribution of AGU-Vallen Wavelet with the kind permission of Prof. Hamstad.

References

• Takemoto M., Nishino H., Ono K., “Wavelet Transform – Applications to AE Signal Analysis”, Acoustic Emission – Beyond the Millenium, Elsevier (2000), pp. 35-56
• Suzuki H., Kinjo T., Hayashi Y., Takemoto M., Ono K., Appendix by Hayashi Y., “Wavelet Transform of Acoustic Emission Signals”, Journal of Acoustic Emission, Vol. 14, No.2 (1996, April-June), pp. 69-84
• Hayashi Y., Ogawa S., Cho H., Takemoto M., “Non-contact estimation of thickness and elastic properties of metallic foils by wavelet transform of laser-generated waves”, NDT and E International, 32-1 (1999, January) pp21-27 (1998)
• Yamada H., Mizutani Y., Nishino H., Takemoto M. Ono K., “Lamb Wave Source Location of Impact on Anisotropic Plates”, Journal of Acoustic Emission, Vol. 18, (2000, December) , pp. 51-60