caa a22 4500 606172785 CHVBK 20210128100730.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s10921-014-0269-1 doi (NATIONALLICENCE)springer-10.1007/s10921-014-0269-1 Nondestructive Material Characterization in the Terahertz Band by Selective Extraction of Sample-Induced Echo Signals [Elektronische Daten] [Jindoo Choi, Won Kwon, Kyung-Soo Kim, Soohyun Kim] Terahertz time-domain spectroscopy (THz-TDS) allows broadband noninvasive measurement of the optical parameters of various materials in the THz domain. The measurement accuracy of these parameters is highly influenced by the difficulty in distinguishing THz signals from unwanted signals such as noise, signal fluctuation, and multiple echoes, which directly affects material identification and characterization efficiency. We introduce a novel method that provides effective extraction and separation of THz signals from such undesired effects. The proposed algorithm was assessed through experiments that presented enhancement in material parameter evaluation, such as the decomposition of the sample-induced echoes (SIEs) from the complex THz sample signal with near-zero extraction error. Improved precision ( $$\pm $$ ± 0.05 $$\,\upmu $$ μ m) was achieved in the determination of the sample thickness compared to that of the mechanical method ( $$\pm $$ ± 10 $$\,\upmu $$ μ m). Furthermore, we could infer from the component concentration measurement results of a compound sample (44.2% decrease in the root mean square concentration error) that the material parameter calculation accuracy had improved, proposing a means to enhance the ultimate nondestructive material evaluation performance. Springer Science+Business Media New York, 2014 Material properties nationallicence Nondestructive inspection nationallicence Terahertz time-domain spectroscopy nationallicence Multiple reflections nationallicence Modelling and analysis techniques nationallicence Choi Jindoo Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea aut Kwon Won Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea aut Kim Kyung-Soo Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea aut Kim Soohyun Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea aut Journal of Nondestructive Evaluation Springer US; http://www.springer-ny.com 34/1(2015-03-01), 1-9 0195-9298 34:1<1 2015 34 10921 https://doi.org/10.1007/s10921-014-0269-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10921-014-0269-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Choi Jindoo Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea aut NATIONALLICENCE 700 1- Kwon Won Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea aut NATIONALLICENCE 700 1- Kim Kyung-Soo Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea aut NATIONALLICENCE 700 1- Kim Soohyun Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea aut NATIONALLICENCE 773 0- Journal of Nondestructive Evaluation Springer US; http://www.springer-ny.com 34/1(2015-03-01), 1-9 0195-9298 34:1<1 2015 34 10921