Abstract

The terahertz (THz) spectra in the range of 0.2–1.6 THz (6.6–52.8 cm−1) of wheat grains with various degrees of deterioration (normal, worm-eaten, moldy, and sprouting wheat grains) were investigated by terahertz time domain spectroscopy. Principal component analysis (PCA) was employed to extract feature data according to the cumulative contribution rates; the top four principal components were selected, and then a support vector machine (SVM) method was applied. Several selection kernels (linear, polynomial, and radial basis functions) were applied to identify the four types of wheat grain. The results showed that the materials were identified with an accuracy of nearly 95%. Furthermore, this approach was compared with others (principal component regression, partial least squares regression, and back-propagation neural networks). The comparisons showed that PCA-SVM outperformed the others and also indicated that the proposed method of THz technology combined with PCA-SVM is efficient and feasible for identifying wheat of different qualities.

© 2014 Optical Society of America

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2013 (7)

I. Amenabar, F. Lopez, A. Mendikute, “In introductory review to THz non-destructive testing of composite mater,” J Infrared, Millimeter, Terahertz Waves 34(2), 152–169 (2013).
[CrossRef]

E. Castro-Camus, M. Palomar, A. A. Covarrubias, “Leaf water dynamics of Arabidopsis thaliana monitored in-vivo using terahertz time-domain spectroscopy,” Sci Rep 3, 2910–2914 (2013).
[CrossRef] [PubMed]

Y. H. Ma, Q. Wang, L. Y. Li, “PLS model investigation of thiabendazole based on THz spectrum,” J. Quant. Spectrosc. Radiat. Transf. 117, 7–14 (2013).
[CrossRef]

R. Gente, N. Born, N. Voß, W. Sannemann, M. K. J. Léon, E. Castro-Camus, “Determination of leaf water content from terahertz time-domain spectroscopic data,” J Infrared, Millimeter, Terahertz Waves 34(3-4), 316–323 (2013).
[CrossRef]

Y. Maali, A. Al-Jumaily, “Self-advising support vector machine,” Knowl. Base. Syst. 52, 214–222 (2013).
[CrossRef]

M. He, G. L. Yang, H. Y. Xie, “A hybrid method to recognize 3D object,” Opt. Express 21(5), 6346–6352 (2013).
[CrossRef] [PubMed]

L. V. Titova, A. K. Ayesheshim, A. Golubov, D. Fogen, R. Rodriguez-Juarez, F. A. Hegmann, O. Kovalchuk, “Intense THz pulses cause H2AX phosphorylation and activate DNA damage response in human skin tissue,” Biomed. Opt. Express 4(4), 559–568 (2013).
[CrossRef] [PubMed]

2012 (5)

T. L. Liu, Q. Y. Su, Q. Sun, L. M. Yang, “Recognition of corn seeds based on pattern recognition and near infrared spectroscopy technology,” Guang Pu Xue Yu Guang Pu Fen Xi 32(5), 1209–1212 (2012).
[PubMed]

K. Schweizer, P. C. Cattin, R. Brunner, B. Müller, C. Huber, J. Romkes, “Automatic selection of a representative trial from multiple measurements using Principle Component Analysis,” J. Biomech. 45(13), 2306–2309 (2012).
[CrossRef] [PubMed]

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

A. A. Gowen, C. OSullivan, C. P. ODonnell, “Terahertz time domain spectroscopy and imaging: Emerging techniques for food process monitoring and quality control,” Trends Food Sci. Technol. 25(1), 40–46 (2012).
[CrossRef]

F. Crista, I. Radulov, L. Crista, A. Berbecea, A. Lato, “Influence of mineral fertilization on the amino acid content and raw protein of wheat grain,” J. Food Agric. Environ. 10, 47–50 (2012).

2011 (2)

J. Eifler, E. Martinelli, M. Santonico, R. Capuano, D. Schild, C. Di Natale, “Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose,” PLoS ONE 6(6), e21026 (2011).
[CrossRef] [PubMed]

Z. Xiao-li, L. Jiu-sheng, “Diagnostic techniques of talc powder in flour based on the THz spectroscopy,” J. Phys. Conf. Ser. 276, 012234 (2011).
[CrossRef]

2010 (4)

C. V. Kandala, J. Sundaram, “Nondestructive measurement of moisture content using a parallel-plate capacitance sensor for grain and nuts,” IEEE Sens. J. 10(7), 1282–1287 (2010).
[CrossRef]

R. Noori, M. S. Sabahi, A. R. Karbassi, A. Baghvand, H. T. Zadeh, “Multivariate statistical analysis of surface water quality based on correlations and variations in the data set,” Desalination 260(1-3), 129–136 (2010).
[CrossRef]

Y. F. Hua, H. J. Zhang, “Qualitative and quantitative detection of pesticides with terahertz time-domain spectroscopy,” IEEE Trans Microw Theory 58(7), 2064–2070 (2010).
[CrossRef]

O. O. Oladunmoye, R. Akinoso, A. A. Olapade, “Evaluation of some physical-chemical properties of wheat, cassava, maize and cowpea flours for bread making,” J. Food Qual. 33(6), 693–708 (2010).
[CrossRef]

2009 (3)

Y. E. Zhang, Q. Q. Chu, H. G. Wang, “Trends and strategies of food security during process of urbanization in China,” Res Agric Modernization 30, 270–274 (2009).

M. Scheller, C. Jansen, M. Koch, “Analyzing sub-100-μm samples with transmission terahertz time domain spectroscopy,” Opt. Commun. 282(7), 1304–1306 (2009).
[CrossRef]

P. C. Ashworth, E. Pickwell-MacPherson, E. Provenzano, S. E. Pinder, A. D. Purushotham, M. Pepper, V. P. Wallace, “Terahertz pulsed spectroscopy of freshly excised human breast cancer,” Opt. Express 17(15), 12444–12454 (2009).
[CrossRef] [PubMed]

2008 (1)

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

2007 (2)

S. Neethirajan, C. Karunakaran, D. S. Jayas, N. D. G. White, “Detection techniques for stored-product insects in grain,” Food Contr. 18(2), 157–162 (2007).
[CrossRef]

I. Pupeza, R. Wilk, M. Koch, “Highly accurate optical material parameter determination with THz time-domain spectroscopy,” Opt. Express 15(7), 4335–4350 (2007).
[CrossRef] [PubMed]

2004 (2)

E. Marengo, M. Bobba, E. Robotti, M. Lenti, “Hydroxyl and acid number prediction in polyester resins by near infrared spectroscopy and artificial neural networks,” Anal. Chim. Acta 511(2), 313–322 (2004).
[CrossRef]

P. H. Siegel, “Terahertz technology in biology and medicine,” IEEE Trans Microw Theory 52(10), 2438–2447 (2004).
[CrossRef]

2002 (1)

B. Ferguson, X. C. Zhang, “Materials for terahertz science and technology,” Nat. Mater. 1(1), 26–33 (2002).
[CrossRef] [PubMed]

2001 (1)

1999 (1)

S. Hadjiloucas, L. S. Karatzas, J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans Microw Theory 47(2), 142–149 (1999).
[CrossRef]

1996 (1)

L. Duvillaret, F. Garet, J. L. Coutaz, “A reliable method for extraction of material parameters in terahertz time-domain spectroscopy,” IEEE J. Sel. Top. Quantum Electron. 2(3), 739–746 (1996).
[CrossRef]

1995 (1)

C. Cortes, V. Vapnik, “Support-vector networks,” Mach. Learn. 20(3), 273–297 (1995).
[CrossRef]

1989 (1)

Akinoso, R.

O. O. Oladunmoye, R. Akinoso, A. A. Olapade, “Evaluation of some physical-chemical properties of wheat, cassava, maize and cowpea flours for bread making,” J. Food Qual. 33(6), 693–708 (2010).
[CrossRef]

Al-Jumaily, A.

Y. Maali, A. Al-Jumaily, “Self-advising support vector machine,” Knowl. Base. Syst. 52, 214–222 (2013).
[CrossRef]

Amenabar, I.

I. Amenabar, F. Lopez, A. Mendikute, “In introductory review to THz non-destructive testing of composite mater,” J Infrared, Millimeter, Terahertz Waves 34(2), 152–169 (2013).
[CrossRef]

Andreoni, W.

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

Ashworth, P. C.

Ayesheshim, A. K.

Baghvand, A.

R. Noori, M. S. Sabahi, A. R. Karbassi, A. Baghvand, H. T. Zadeh, “Multivariate statistical analysis of surface water quality based on correlations and variations in the data set,” Desalination 260(1-3), 129–136 (2010).
[CrossRef]

Baraniuk, R. G.

Berbecea, A.

F. Crista, I. Radulov, L. Crista, A. Berbecea, A. Lato, “Influence of mineral fertilization on the amino acid content and raw protein of wheat grain,” J. Food Agric. Environ. 10, 47–50 (2012).

Bobba, M.

E. Marengo, M. Bobba, E. Robotti, M. Lenti, “Hydroxyl and acid number prediction in polyester resins by near infrared spectroscopy and artificial neural networks,” Anal. Chim. Acta 511(2), 313–322 (2004).
[CrossRef]

Born, N.

R. Gente, N. Born, N. Voß, W. Sannemann, M. K. J. Léon, E. Castro-Camus, “Determination of leaf water content from terahertz time-domain spectroscopic data,” J Infrared, Millimeter, Terahertz Waves 34(3-4), 316–323 (2013).
[CrossRef]

Bowen, J. W.

S. Hadjiloucas, L. S. Karatzas, J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans Microw Theory 47(2), 142–149 (1999).
[CrossRef]

Brunner, R.

K. Schweizer, P. C. Cattin, R. Brunner, B. Müller, C. Huber, J. Romkes, “Automatic selection of a representative trial from multiple measurements using Principle Component Analysis,” J. Biomech. 45(13), 2306–2309 (2012).
[CrossRef] [PubMed]

Capuano, R.

J. Eifler, E. Martinelli, M. Santonico, R. Capuano, D. Schild, C. Di Natale, “Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose,” PLoS ONE 6(6), e21026 (2011).
[CrossRef] [PubMed]

Castro-Camus, E.

E. Castro-Camus, M. Palomar, A. A. Covarrubias, “Leaf water dynamics of Arabidopsis thaliana monitored in-vivo using terahertz time-domain spectroscopy,” Sci Rep 3, 2910–2914 (2013).
[CrossRef] [PubMed]

R. Gente, N. Born, N. Voß, W. Sannemann, M. K. J. Léon, E. Castro-Camus, “Determination of leaf water content from terahertz time-domain spectroscopic data,” J Infrared, Millimeter, Terahertz Waves 34(3-4), 316–323 (2013).
[CrossRef]

Cattin, P. C.

K. Schweizer, P. C. Cattin, R. Brunner, B. Müller, C. Huber, J. Romkes, “Automatic selection of a representative trial from multiple measurements using Principle Component Analysis,” J. Biomech. 45(13), 2306–2309 (2012).
[CrossRef] [PubMed]

Cha, K.

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Chen, J.

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

Chen, Y.

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

Choi, H.

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Chu, Q. Q.

Y. E. Zhang, Q. Q. Chu, H. G. Wang, “Trends and strategies of food security during process of urbanization in China,” Res Agric Modernization 30, 270–274 (2009).

Chung, H.

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Cortes, C.

C. Cortes, V. Vapnik, “Support-vector networks,” Mach. Learn. 20(3), 273–297 (1995).
[CrossRef]

Coutaz, J. L.

L. Duvillaret, F. Garet, J. L. Coutaz, “A reliable method for extraction of material parameters in terahertz time-domain spectroscopy,” IEEE J. Sel. Top. Quantum Electron. 2(3), 739–746 (1996).
[CrossRef]

Covarrubias, A. A.

E. Castro-Camus, M. Palomar, A. A. Covarrubias, “Leaf water dynamics of Arabidopsis thaliana monitored in-vivo using terahertz time-domain spectroscopy,” Sci Rep 3, 2910–2914 (2013).
[CrossRef] [PubMed]

Crista, F.

F. Crista, I. Radulov, L. Crista, A. Berbecea, A. Lato, “Influence of mineral fertilization on the amino acid content and raw protein of wheat grain,” J. Food Agric. Environ. 10, 47–50 (2012).

Crista, L.

F. Crista, I. Radulov, L. Crista, A. Berbecea, A. Lato, “Influence of mineral fertilization on the amino acid content and raw protein of wheat grain,” J. Food Agric. Environ. 10, 47–50 (2012).

Curioni, A.

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

Di Natale, C.

J. Eifler, E. Martinelli, M. Santonico, R. Capuano, D. Schild, C. Di Natale, “Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose,” PLoS ONE 6(6), e21026 (2011).
[CrossRef] [PubMed]

Dorney, T. D.

Duvillaret, L.

L. Duvillaret, F. Garet, J. L. Coutaz, “A reliable method for extraction of material parameters in terahertz time-domain spectroscopy,” IEEE J. Sel. Top. Quantum Electron. 2(3), 739–746 (1996).
[CrossRef]

Eifler, J.

J. Eifler, E. Martinelli, M. Santonico, R. Capuano, D. Schild, C. Di Natale, “Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose,” PLoS ONE 6(6), e21026 (2011).
[CrossRef] [PubMed]

Ferguson, B.

B. Ferguson, X. C. Zhang, “Materials for terahertz science and technology,” Nat. Mater. 1(1), 26–33 (2002).
[CrossRef] [PubMed]

Fogen, D.

Garet, F.

L. Duvillaret, F. Garet, J. L. Coutaz, “A reliable method for extraction of material parameters in terahertz time-domain spectroscopy,” IEEE J. Sel. Top. Quantum Electron. 2(3), 739–746 (1996).
[CrossRef]

Gente, R.

R. Gente, N. Born, N. Voß, W. Sannemann, M. K. J. Léon, E. Castro-Camus, “Determination of leaf water content from terahertz time-domain spectroscopic data,” J Infrared, Millimeter, Terahertz Waves 34(3-4), 316–323 (2013).
[CrossRef]

Golubov, A.

Gowen, A. A.

A. A. Gowen, C. OSullivan, C. P. ODonnell, “Terahertz time domain spectroscopy and imaging: Emerging techniques for food process monitoring and quality control,” Trends Food Sci. Technol. 25(1), 40–46 (2012).
[CrossRef]

Hadjiloucas, S.

S. Hadjiloucas, L. S. Karatzas, J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans Microw Theory 47(2), 142–149 (1999).
[CrossRef]

Hallikainen, J.

He, M.

Hegmann, F. A.

Hua, Y. F.

Y. F. Hua, H. J. Zhang, “Qualitative and quantitative detection of pesticides with terahertz time-domain spectroscopy,” IEEE Trans Microw Theory 58(7), 2064–2070 (2010).
[CrossRef]

Huber, C.

K. Schweizer, P. C. Cattin, R. Brunner, B. Müller, C. Huber, J. Romkes, “Automatic selection of a representative trial from multiple measurements using Principle Component Analysis,” J. Biomech. 45(13), 2306–2309 (2012).
[CrossRef] [PubMed]

Jaaskelainen, T.

Jansen, C.

M. Scheller, C. Jansen, M. Koch, “Analyzing sub-100-μm samples with transmission terahertz time domain spectroscopy,” Opt. Commun. 282(7), 1304–1306 (2009).
[CrossRef]

Jayas, D. S.

S. Neethirajan, C. Karunakaran, D. S. Jayas, N. D. G. White, “Detection techniques for stored-product insects in grain,” Food Contr. 18(2), 157–162 (2007).
[CrossRef]

Jiu-sheng, L.

Z. Xiao-li, L. Jiu-sheng, “Diagnostic techniques of talc powder in flour based on the THz spectroscopy,” J. Phys. Conf. Ser. 276, 012234 (2011).
[CrossRef]

Kandala, C. V.

C. V. Kandala, J. Sundaram, “Nondestructive measurement of moisture content using a parallel-plate capacitance sensor for grain and nuts,” IEEE Sens. J. 10(7), 1282–1287 (2010).
[CrossRef]

Karatzas, L. S.

S. Hadjiloucas, L. S. Karatzas, J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans Microw Theory 47(2), 142–149 (1999).
[CrossRef]

Karbassi, A. R.

R. Noori, M. S. Sabahi, A. R. Karbassi, A. Baghvand, H. T. Zadeh, “Multivariate statistical analysis of surface water quality based on correlations and variations in the data set,” Desalination 260(1-3), 129–136 (2010).
[CrossRef]

Karunakaran, C.

S. Neethirajan, C. Karunakaran, D. S. Jayas, N. D. G. White, “Detection techniques for stored-product insects in grain,” Food Contr. 18(2), 157–162 (2007).
[CrossRef]

Kim, J. S.

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Kim, M. K.

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Koch, M.

M. Scheller, C. Jansen, M. Koch, “Analyzing sub-100-μm samples with transmission terahertz time domain spectroscopy,” Opt. Commun. 282(7), 1304–1306 (2009).
[CrossRef]

I. Pupeza, R. Wilk, M. Koch, “Highly accurate optical material parameter determination with THz time-domain spectroscopy,” Opt. Express 15(7), 4335–4350 (2007).
[CrossRef] [PubMed]

Kovalchuk, O.

Lato, A.

F. Crista, I. Radulov, L. Crista, A. Berbecea, A. Lato, “Influence of mineral fertilization on the amino acid content and raw protein of wheat grain,” J. Food Agric. Environ. 10, 47–50 (2012).

Lee, S.

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Lee, S. H.

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Lenti, M.

E. Marengo, M. Bobba, E. Robotti, M. Lenti, “Hydroxyl and acid number prediction in polyester resins by near infrared spectroscopy and artificial neural networks,” Anal. Chim. Acta 511(2), 313–322 (2004).
[CrossRef]

Léon, M. K. J.

R. Gente, N. Born, N. Voß, W. Sannemann, M. K. J. Léon, E. Castro-Camus, “Determination of leaf water content from terahertz time-domain spectroscopic data,” J Infrared, Millimeter, Terahertz Waves 34(3-4), 316–323 (2013).
[CrossRef]

Li, L. Y.

Y. H. Ma, Q. Wang, L. Y. Li, “PLS model investigation of thiabendazole based on THz spectrum,” J. Quant. Spectrosc. Radiat. Transf. 117, 7–14 (2013).
[CrossRef]

Liu, T. L.

T. L. Liu, Q. Y. Su, Q. Sun, L. M. Yang, “Recognition of corn seeds based on pattern recognition and near infrared spectroscopy technology,” Guang Pu Xue Yu Guang Pu Fen Xi 32(5), 1209–1212 (2012).
[PubMed]

Lopez, F.

I. Amenabar, F. Lopez, A. Mendikute, “In introductory review to THz non-destructive testing of composite mater,” J Infrared, Millimeter, Terahertz Waves 34(2), 152–169 (2013).
[CrossRef]

Ma, Y. H.

Y. H. Ma, Q. Wang, L. Y. Li, “PLS model investigation of thiabendazole based on THz spectrum,” J. Quant. Spectrosc. Radiat. Transf. 117, 7–14 (2013).
[CrossRef]

Maali, Y.

Y. Maali, A. Al-Jumaily, “Self-advising support vector machine,” Knowl. Base. Syst. 52, 214–222 (2013).
[CrossRef]

Marengo, E.

E. Marengo, M. Bobba, E. Robotti, M. Lenti, “Hydroxyl and acid number prediction in polyester resins by near infrared spectroscopy and artificial neural networks,” Anal. Chim. Acta 511(2), 313–322 (2004).
[CrossRef]

Martinelli, E.

J. Eifler, E. Martinelli, M. Santonico, R. Capuano, D. Schild, C. Di Natale, “Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose,” PLoS ONE 6(6), e21026 (2011).
[CrossRef] [PubMed]

Mendikute, A.

I. Amenabar, F. Lopez, A. Mendikute, “In introductory review to THz non-destructive testing of composite mater,” J Infrared, Millimeter, Terahertz Waves 34(2), 152–169 (2013).
[CrossRef]

Mittleman, D. M.

Müller, B.

K. Schweizer, P. C. Cattin, R. Brunner, B. Müller, C. Huber, J. Romkes, “Automatic selection of a representative trial from multiple measurements using Principle Component Analysis,” J. Biomech. 45(13), 2306–2309 (2012).
[CrossRef] [PubMed]

Nayak, S. K.

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

Neethirajan, S.

S. Neethirajan, C. Karunakaran, D. S. Jayas, N. D. G. White, “Detection techniques for stored-product insects in grain,” Food Contr. 18(2), 157–162 (2007).
[CrossRef]

Noori, R.

R. Noori, M. S. Sabahi, A. R. Karbassi, A. Baghvand, H. T. Zadeh, “Multivariate statistical analysis of surface water quality based on correlations and variations in the data set,” Desalination 260(1-3), 129–136 (2010).
[CrossRef]

ODonnell, C. P.

A. A. Gowen, C. OSullivan, C. P. ODonnell, “Terahertz time domain spectroscopy and imaging: Emerging techniques for food process monitoring and quality control,” Trends Food Sci. Technol. 25(1), 40–46 (2012).
[CrossRef]

Oladunmoye, O. O.

O. O. Oladunmoye, R. Akinoso, A. A. Olapade, “Evaluation of some physical-chemical properties of wheat, cassava, maize and cowpea flours for bread making,” J. Food Qual. 33(6), 693–708 (2010).
[CrossRef]

Olapade, A. A.

O. O. Oladunmoye, R. Akinoso, A. A. Olapade, “Evaluation of some physical-chemical properties of wheat, cassava, maize and cowpea flours for bread making,” J. Food Qual. 33(6), 693–708 (2010).
[CrossRef]

OSullivan, C.

A. A. Gowen, C. OSullivan, C. P. ODonnell, “Terahertz time domain spectroscopy and imaging: Emerging techniques for food process monitoring and quality control,” Trends Food Sci. Technol. 25(1), 40–46 (2012).
[CrossRef]

Palomar, M.

E. Castro-Camus, M. Palomar, A. A. Covarrubias, “Leaf water dynamics of Arabidopsis thaliana monitored in-vivo using terahertz time-domain spectroscopy,” Sci Rep 3, 2910–2914 (2013).
[CrossRef] [PubMed]

Parkkinen, J. P. S.

Peng, X. H.

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

Pepper, M.

Pickwell-MacPherson, E.

Pinder, S. E.

Provenzano, E.

Pupeza, I.

Purushotham, A. D.

Radulov, I.

F. Crista, I. Radulov, L. Crista, A. Berbecea, A. Lato, “Influence of mineral fertilization on the amino acid content and raw protein of wheat grain,” J. Food Agric. Environ. 10, 47–50 (2012).

Robotti, E.

E. Marengo, M. Bobba, E. Robotti, M. Lenti, “Hydroxyl and acid number prediction in polyester resins by near infrared spectroscopy and artificial neural networks,” Anal. Chim. Acta 511(2), 313–322 (2004).
[CrossRef]

Rodriguez-Juarez, R.

Romkes, J.

K. Schweizer, P. C. Cattin, R. Brunner, B. Müller, C. Huber, J. Romkes, “Automatic selection of a representative trial from multiple measurements using Principle Component Analysis,” J. Biomech. 45(13), 2306–2309 (2012).
[CrossRef] [PubMed]

Sabahi, M. S.

R. Noori, M. S. Sabahi, A. R. Karbassi, A. Baghvand, H. T. Zadeh, “Multivariate statistical analysis of surface water quality based on correlations and variations in the data set,” Desalination 260(1-3), 129–136 (2010).
[CrossRef]

Sannemann, W.

R. Gente, N. Born, N. Voß, W. Sannemann, M. K. J. Léon, E. Castro-Camus, “Determination of leaf water content from terahertz time-domain spectroscopic data,” J Infrared, Millimeter, Terahertz Waves 34(3-4), 316–323 (2013).
[CrossRef]

Santonico, M.

J. Eifler, E. Martinelli, M. Santonico, R. Capuano, D. Schild, C. Di Natale, “Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose,” PLoS ONE 6(6), e21026 (2011).
[CrossRef] [PubMed]

Scheller, M.

M. Scheller, C. Jansen, M. Koch, “Analyzing sub-100-μm samples with transmission terahertz time domain spectroscopy,” Opt. Commun. 282(7), 1304–1306 (2009).
[CrossRef]

Schild, D.

J. Eifler, E. Martinelli, M. Santonico, R. Capuano, D. Schild, C. Di Natale, “Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose,” PLoS ONE 6(6), e21026 (2011).
[CrossRef] [PubMed]

Schweizer, K.

K. Schweizer, P. C. Cattin, R. Brunner, B. Müller, C. Huber, J. Romkes, “Automatic selection of a representative trial from multiple measurements using Principle Component Analysis,” J. Biomech. 45(13), 2306–2309 (2012).
[CrossRef] [PubMed]

Siegel, P. H.

P. H. Siegel, “Terahertz technology in biology and medicine,” IEEE Trans Microw Theory 52(10), 2438–2447 (2004).
[CrossRef]

Su, Q. Y.

T. L. Liu, Q. Y. Su, Q. Sun, L. M. Yang, “Recognition of corn seeds based on pattern recognition and near infrared spectroscopy technology,” Guang Pu Xue Yu Guang Pu Fen Xi 32(5), 1209–1212 (2012).
[PubMed]

Sun, Q.

T. L. Liu, Q. Y. Su, Q. Sun, L. M. Yang, “Recognition of corn seeds based on pattern recognition and near infrared spectroscopy technology,” Guang Pu Xue Yu Guang Pu Fen Xi 32(5), 1209–1212 (2012).
[PubMed]

Sundaram, J.

C. V. Kandala, J. Sundaram, “Nondestructive measurement of moisture content using a parallel-plate capacitance sensor for grain and nuts,” IEEE Sens. J. 10(7), 1282–1287 (2010).
[CrossRef]

Titova, L. V.

Vapnik, V.

C. Cortes, V. Vapnik, “Support-vector networks,” Mach. Learn. 20(3), 273–297 (1995).
[CrossRef]

Voß, N.

R. Gente, N. Born, N. Voß, W. Sannemann, M. K. J. Léon, E. Castro-Camus, “Determination of leaf water content from terahertz time-domain spectroscopic data,” J Infrared, Millimeter, Terahertz Waves 34(3-4), 316–323 (2013).
[CrossRef]

Wallace, V. P.

Wang, H. G.

Y. E. Zhang, Q. Q. Chu, H. G. Wang, “Trends and strategies of food security during process of urbanization in China,” Res Agric Modernization 30, 270–274 (2009).

Wang, Q.

Y. H. Ma, Q. Wang, L. Y. Li, “PLS model investigation of thiabendazole based on THz spectrum,” J. Quant. Spectrosc. Radiat. Transf. 117, 7–14 (2013).
[CrossRef]

White, N. D. G.

S. Neethirajan, C. Karunakaran, D. S. Jayas, N. D. G. White, “Detection techniques for stored-product insects in grain,” Food Contr. 18(2), 157–162 (2007).
[CrossRef]

Wilk, R.

Xiao-li, Z.

Z. Xiao-li, L. Jiu-sheng, “Diagnostic techniques of talc powder in flour based on the THz spectroscopy,” J. Phys. Conf. Ser. 276, 012234 (2011).
[CrossRef]

Xie, H. Y.

Yang, G. L.

Yang, L. M.

T. L. Liu, Q. Y. Su, Q. Sun, L. M. Yang, “Recognition of corn seeds based on pattern recognition and near infrared spectroscopy technology,” Guang Pu Xue Yu Guang Pu Fen Xi 32(5), 1209–1212 (2012).
[PubMed]

Youn, C. H.

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Zadeh, H. T.

R. Noori, M. S. Sabahi, A. R. Karbassi, A. Baghvand, H. T. Zadeh, “Multivariate statistical analysis of surface water quality based on correlations and variations in the data set,” Desalination 260(1-3), 129–136 (2010).
[CrossRef]

Zhang, H. J.

Y. F. Hua, H. J. Zhang, “Qualitative and quantitative detection of pesticides with terahertz time-domain spectroscopy,” IEEE Trans Microw Theory 58(7), 2064–2070 (2010).
[CrossRef]

Zhang, X. C.

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

B. Ferguson, X. C. Zhang, “Materials for terahertz science and technology,” Nat. Mater. 1(1), 26–33 (2002).
[CrossRef] [PubMed]

Zhang, Y.

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

Zhang, Y. E.

Y. E. Zhang, Q. Q. Chu, H. G. Wang, “Trends and strategies of food security during process of urbanization in China,” Res Agric Modernization 30, 270–274 (2009).

Anal. Chim. Acta (1)

E. Marengo, M. Bobba, E. Robotti, M. Lenti, “Hydroxyl and acid number prediction in polyester resins by near infrared spectroscopy and artificial neural networks,” Anal. Chim. Acta 511(2), 313–322 (2004).
[CrossRef]

Biomed. Opt. Express (1)

Bull. Korean Chem. Soc. (1)

S. Lee, H. Choi, K. Cha, M. K. Kim, J. S. Kim, C. H. Youn, S. H. Lee, H. Chung, “Random forest as a non-parametric algorithm for near-infrared (NIR) spectroscopic discrimination for geographical origin of agricultural samples,” Bull. Korean Chem. Soc. 33(12), 4267–4270 (2012).
[CrossRef]

Chem. Phys. Lett. (1)

Y. Zhang, X. H. Peng, Y. Chen, J. Chen, A. Curioni, W. Andreoni, S. K. Nayak, X. C. Zhang, “A first principle study of terahertz (THz) spectra of acephate,” Chem. Phys. Lett. 452(1-3), 59–66 (2008).
[CrossRef]

Desalination (1)

R. Noori, M. S. Sabahi, A. R. Karbassi, A. Baghvand, H. T. Zadeh, “Multivariate statistical analysis of surface water quality based on correlations and variations in the data set,” Desalination 260(1-3), 129–136 (2010).
[CrossRef]

Food Contr. (1)

S. Neethirajan, C. Karunakaran, D. S. Jayas, N. D. G. White, “Detection techniques for stored-product insects in grain,” Food Contr. 18(2), 157–162 (2007).
[CrossRef]

Guang Pu Xue Yu Guang Pu Fen Xi (1)

T. L. Liu, Q. Y. Su, Q. Sun, L. M. Yang, “Recognition of corn seeds based on pattern recognition and near infrared spectroscopy technology,” Guang Pu Xue Yu Guang Pu Fen Xi 32(5), 1209–1212 (2012).
[PubMed]

IEEE J. Sel. Top. Quantum Electron. (1)

L. Duvillaret, F. Garet, J. L. Coutaz, “A reliable method for extraction of material parameters in terahertz time-domain spectroscopy,” IEEE J. Sel. Top. Quantum Electron. 2(3), 739–746 (1996).
[CrossRef]

IEEE Sens. J. (1)

C. V. Kandala, J. Sundaram, “Nondestructive measurement of moisture content using a parallel-plate capacitance sensor for grain and nuts,” IEEE Sens. J. 10(7), 1282–1287 (2010).
[CrossRef]

IEEE Trans Microw Theory (3)

P. H. Siegel, “Terahertz technology in biology and medicine,” IEEE Trans Microw Theory 52(10), 2438–2447 (2004).
[CrossRef]

S. Hadjiloucas, L. S. Karatzas, J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans Microw Theory 47(2), 142–149 (1999).
[CrossRef]

Y. F. Hua, H. J. Zhang, “Qualitative and quantitative detection of pesticides with terahertz time-domain spectroscopy,” IEEE Trans Microw Theory 58(7), 2064–2070 (2010).
[CrossRef]

J Infrared, Millimeter, Terahertz Waves (2)

I. Amenabar, F. Lopez, A. Mendikute, “In introductory review to THz non-destructive testing of composite mater,” J Infrared, Millimeter, Terahertz Waves 34(2), 152–169 (2013).
[CrossRef]

R. Gente, N. Born, N. Voß, W. Sannemann, M. K. J. Léon, E. Castro-Camus, “Determination of leaf water content from terahertz time-domain spectroscopic data,” J Infrared, Millimeter, Terahertz Waves 34(3-4), 316–323 (2013).
[CrossRef]

J. Biomech. (1)

K. Schweizer, P. C. Cattin, R. Brunner, B. Müller, C. Huber, J. Romkes, “Automatic selection of a representative trial from multiple measurements using Principle Component Analysis,” J. Biomech. 45(13), 2306–2309 (2012).
[CrossRef] [PubMed]

J. Food Agric. Environ. (1)

F. Crista, I. Radulov, L. Crista, A. Berbecea, A. Lato, “Influence of mineral fertilization on the amino acid content and raw protein of wheat grain,” J. Food Agric. Environ. 10, 47–50 (2012).

J. Food Qual. (1)

O. O. Oladunmoye, R. Akinoso, A. A. Olapade, “Evaluation of some physical-chemical properties of wheat, cassava, maize and cowpea flours for bread making,” J. Food Qual. 33(6), 693–708 (2010).
[CrossRef]

J. Opt. Soc. Am. A (2)

J. Phys. Conf. Ser. (1)

Z. Xiao-li, L. Jiu-sheng, “Diagnostic techniques of talc powder in flour based on the THz spectroscopy,” J. Phys. Conf. Ser. 276, 012234 (2011).
[CrossRef]

J. Quant. Spectrosc. Radiat. Transf. (1)

Y. H. Ma, Q. Wang, L. Y. Li, “PLS model investigation of thiabendazole based on THz spectrum,” J. Quant. Spectrosc. Radiat. Transf. 117, 7–14 (2013).
[CrossRef]

Knowl. Base. Syst. (1)

Y. Maali, A. Al-Jumaily, “Self-advising support vector machine,” Knowl. Base. Syst. 52, 214–222 (2013).
[CrossRef]

Mach. Learn. (1)

C. Cortes, V. Vapnik, “Support-vector networks,” Mach. Learn. 20(3), 273–297 (1995).
[CrossRef]

Nat. Mater. (1)

B. Ferguson, X. C. Zhang, “Materials for terahertz science and technology,” Nat. Mater. 1(1), 26–33 (2002).
[CrossRef] [PubMed]

Opt. Commun. (1)

M. Scheller, C. Jansen, M. Koch, “Analyzing sub-100-μm samples with transmission terahertz time domain spectroscopy,” Opt. Commun. 282(7), 1304–1306 (2009).
[CrossRef]

Opt. Express (3)

PLoS ONE (1)

J. Eifler, E. Martinelli, M. Santonico, R. Capuano, D. Schild, C. Di Natale, “Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose,” PLoS ONE 6(6), e21026 (2011).
[CrossRef] [PubMed]

Res Agric Modernization (1)

Y. E. Zhang, Q. Q. Chu, H. G. Wang, “Trends and strategies of food security during process of urbanization in China,” Res Agric Modernization 30, 270–274 (2009).

Sci Rep (1)

E. Castro-Camus, M. Palomar, A. A. Covarrubias, “Leaf water dynamics of Arabidopsis thaliana monitored in-vivo using terahertz time-domain spectroscopy,” Sci Rep 3, 2910–2914 (2013).
[CrossRef] [PubMed]

Trends Food Sci. Technol. (1)

A. A. Gowen, C. OSullivan, C. P. ODonnell, “Terahertz time domain spectroscopy and imaging: Emerging techniques for food process monitoring and quality control,” Trends Food Sci. Technol. 25(1), 40–46 (2012).
[CrossRef]

Other (4)

L. Y. Guo, “Reduce grain loss and combat food waste,” China Grain Econ. 17-18 (2013).

L. L. Wu, J. Wu, Y. X. Wen, L. R. Xiong, and Y. Zheng, “Classification of single cereal grain kernel using shape parameters based on machine vision,” in Advanced Designs and Researches for Manufacturing, Pts. 1–3, P. C. Wang, X. D. Liu, and Y. Q. Han, eds. (Trans Tech Publications Ltd., Stafa-Zurich, 2013), pp. 2179–2182.

H. L. Zhou, Research on Intelligent Multifunction Monitoring and Control System Platform For Grain Storage (Beijing University of Posts and Telecommunications, 2010).

N. Cristianini and J. Shawe-Taylor, An Introduction to Support Vector Machines and Other Kernel-Based Learning Methods (Cambridge University Press, Cambridge, 2000).

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Figures (6)

Fig. 1
Fig. 1

Schematic diagram of THz TDS. HWP: Half-wave plate, BS: Beam splitter, PM: Parabolic mirror, L: Lens, P: Polarizer, QWP: Quarter-wave plate, PBS: Polarizing beam splitter.

Fig. 2
Fig. 2

Time-domain THz pulses of reference and samples.

Fig. 3
Fig. 3

Average absorption spectra of four types of wheat.

Fig. 4
Fig. 4

PCA scores plots for 120 samples.

Fig. 5
Fig. 5

Parameter γ versus RMSE for SVM model.

Fig. 6
Fig. 6

Parameter γ versus RMSE for the PCA-SVM model.

Tables (4)

Tables Icon

Table 1 Four Types of Wheat Used in Experiment

Tables Icon

Table 2 Results of Validation of SVM

Tables Icon

Table 3 Results of Validation of PCA-SVM

Tables Icon

Table 4 Identification Accuracies of Different Models for Four Wheat Types

Equations (13)

Equations on this page are rendered with MathJax. Learn more.

N(ω)=n(ω)ik(ω),
H(ω)= E s (ω) E ref (ω) = 4N (N+1) 2 exp( iω(N1)d c )=ρ(ω)exp(iϕ(ω)),
n(ω)= ϕ(ω) ωd c+1,
a(ω)= 2 d ln( 4n(ω) ρ(ω) [n(ω)+1] 2 )
X i * = X i mean( X i ) std( X i ) , (i=1,2,,n).
{( x 1 , y 1 ),( x 2 , y 2 ),( x k , y k )} R d ×R.
1 2 w T w+C i=1 N ξ i +C i=1 N ξ i * ,
w T ϕ( X i )+b y i ε+ ξ * i , y i w T ϕ( X i )bε+ ξ i , ξ * i , ξ i 0 , i=1,2,,n,
i=1 n y i ( α i α i * ) ε i=1 n ( α i + α i * ) 1 2 i=1 n j=1 n ( α i α i * )( α j α j * ) ϕ ( x i ) T ϕ( x j ),
i=1 n ( α i α i * ) =0 0 α i , α i * C i=1,2,,n
f(x)= i=1 n ( α i α i * ) ϕ ( x i ) T ϕ(x)+b.
f(x)= i=1 n α ¯ i ϕ ( x i ) T ϕ(x)+b.
RMSE= i=1 N ( Y i Y ^ i ) 2 N ,

Metrics