Faculty Profiles - INAGAKI Tetsuya

Papers - INAGAKI Tetsuya

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Terahertz time-domain spectroscopy as a novel tool for crystallographic analysis in cellulose Reviewed

Han Wang, Yoshiki Horikawa, Satoru Tsuchikawa, Tetsuya Inagaki

CELLULOSE Vol. 27 ( 17 ) page： 9767 - 9777 2020.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Terahertz (THz) radiation is responsive to optical phonons in crystal lattices; therefore, THz time-domain spectroscopy (THz-TDS) has potential utility in crystallographic analysis. In this study, THz-TDS was used to investigate cellulose samples extracted from different sources with varying ratios of I(alpha)and I(beta)fractions. This is the first study to report that the absorption coefficient in the THz region of cellulose I(alpha)and I(beta)presents different characteristic absorption peaks around 2 THz. This can be used to distinguish the cellulose I allomorph, which exhibits differences in its crystalline structure. The absorption coefficient at 2.11 and 2.38 THz showed a considerable linear correlation with the I(alpha)fraction of the cellulose samples. The absorption coefficient spectra of 1.88-3.40 THz were further detrended and separated into three Gaussian peaks. The correlations between the parameters of these separated peaks (integrated intensities, peak positions) and the crystalline structural values (d-spacing, crystalline size, crystallinity index) that calculated from the X-ray diffraction (XRD) pattern were investigated.

DOI： 10.1007/s10570-020-03508-9

Rapid and non-destructive seed viability prediction using near-infrared hyperspectral imaging coupled with a deep learning approach Reviewed

Te Ma, Satoru Tsuchikawa, Tetsuya Inagaki

COMPUTERS AND ELECTRONICS IN AGRICULTURE Vol. 177 2020.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

Seeds are the basis of the agricultural food industry, greater insights into seed viability before sowing could improve storage management and field performance. In the present study, we aimed to address this issue by using highly cost-efficient near-infrared hyperspectral imaging (NIR-HSI) and a convolutional neural network (CNN) deep learning approach. An NIR-HSI camera was used because it can recognize both molecular vibration information (i.e. chemical component differences) and its spatial distribution in each seed sample; this camera is much more informative than a regular RGB digital camera. Using this technology, the emphasis of this study was firstly to provide a methodology for enhancing the interpretability of viable and non-viable seeds via principal component analysis (PCA) and support vector machine (SVM) viability classification analysis of NIR-HSI data. A CNN was then constructed to"cognize" the differences in viable and non-inviable seeds and classify them automatically. Experimental results indicate that the methodology produces a similar to 90% classification accuracy for both a five-fold cross-validation set and a test set of naturally aged Japanese mustard spinach seeds. Therefore, this study provides a new strategy for effective and practical seed viability prediction.

DOI： 10.1016/j.compag.2020.105683

Physical and Mechanical Properties of Fast Growing Polyploid Acacia Hybrids (A. auriculiformisxA. mangium) from Vietnam Reviewed International coauthorship Open Access

Dang Duc Viet, Te Ma, Tetsuya Inagaki, Nguyen Tu Kim, Nghiem Quynh Chi, Satoru Tsuchikawa

FORESTS Vol. 11 ( 7 ) 2020.7

Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI

Acacia plants are globally important resources in the wood industry, but particularly in Southeast Asian countries. In the present study, we compared the physical and mechanical properties of polyploidAcacia(3x and 4x) clones with those of diploid (2x) clones grown in Vietnam. We randomly selected 29 trees aged 3.8 years from different taxa for investigation. BV10 and BV16 clones represented the diploid controls; X101 and X102 were the triploid clones; and AA-4x, AM-4x, and AH-4x represented neo-tetraploid families ofAcaciaauriculiformis, Acaciamangium,and their hybrid clones. The following metrics were measured in each plant: stem height levels, basic density, air-dry equilibrium moisture content, modulus of rupture (MOR), modulus of elasticity (MOE), compression strength, and Young's modulus. We found that the equilibrium moisture content significantly differed among clones, and basic density varied from pith-to-bark and in an axial direction. In addition, the basic density of AA-4x was significantly higher than that of the control clones. Furthermore, the MOR of AM-4x was considerably lower than the control clones, whereas the MOE of X101 was significantly higher than the control values. The compression strength of AM-4x was significantly lower than that of the control clones, but AH-4x had a significantly higher Young's modulus. Our results suggest that polyploidAcaciahybrids have the potential to be alternative species for providing wood with improved properties to the forestry sector of Vietnam. Furthermore, the significant differences among the clones indicate that opportunities exist for selection and the improvement of wood quality via selective breeding for specific properties.

DOI： 10.3390/f11070717

Rapidly visualizing the dynamic state of free, weakly, and strongly hydrogen-bonded water with lignocellulosic material during drying by near-infrared hyperspectral imaging Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

CELLULOSE Vol. 27 ( 9 ) page： 4857 - 4869 2020.6

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Real-time monitoring of the dynamic state of water molecular structure in lignocellulosic material is challenging, but important for both theoretical studies and industrial applications. In the present study, three typical wood samples which have a fundamental difference in the anatomical structure were scanned in the near-infrared spectral range, and images were acquired from wavelengths of 1002-1847 nm during drying. Then, partial least squares regression was used to determine the water content by mass, and principal component analysis was utilized to characterize the variance of NIR difference spectral data between 1340 and 1610 nm after baseline correlation for showing the distribution changing from free water to bound water during air drying. It was clarified that the PC1 loading mainly correlates with simple water content by mass, whereas the PC2 loading contains information about water-wood hydrogen structure interactions. The three loading curve peaks of PC2 could be correlated with free, weakly bound, and strongly bound water based on longer wavelength shifting. Finally, PC1 and PC2 scores were comprehensively applied to show the distribution changing from free water to bound water in each wood sample with a 62.5 mu m/pixel high spatial resolution.

DOI： 10.1007/s10570-020-03117-6

Simultaneous detection of density, moisture content and fiber direction of wood by THz-time domain spectroscopy Reviewed

M. Kashima, S. Tsuchikawa, T. Inagaki

Journal of Wood Science Vol. 66 page： 27 2020.4

Cognitive spectroscopy for wood species identification: near infrared hyperspectral imaging combined with convolutional neural networks Reviewed

Hideaki Kanayama, Te Ma, Satoru Tsuchikawa, Tetsuya Inagaki

ANALYST Vol. 144 ( 21 ) page： 6438 - 6446 2019.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

From the viewpoint of combating illegal logging and examining wood properties, there is a contemporary demand for a wood species identification system. Several nondestructive automatic identification systems have been developed, but there is room for improvement to construct a highly reliable model. The present study proposes cognitive spectroscopy that combines near infrared hyperspectral imaging (NIR-HSI) with a deep convolutional neural network approach. We defined "cognitive spectroscopy" as a protocol that extracts features from complex spectroscopic data and presents the best results without human intervention. Overall, 120 samples representing 38 hardwood species were scanned using an NIR-HSI camera. A deep learning prediction model was built based on the principal component (PC) images obtained from the PC scores of hyperspectral images (wavelength range: 1000-2200 nm at approximately 6.2 nm interval). The results showed that the accuracy of wood species identification based on 6PC (PC1-PC6) images was 90.5%, which was considerably higher than the accuracy of 56.0% obtained with conventional visible images.

DOI： 10.1039/c9an01180c

Analysis of wood thermal degradation using 2D correlation of near infrared and visible-light spectroscopy Reviewed

Siti Hanifah Mahdiyanti, Tetsuya Inagaki, Satoru Tsuchikawa

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 27 ( 5 ) page： 354 - 369 2019.10

Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

Wood changes its properties, especially color, as a result of thermal degradation. In this study, change in wood properties due to thermal degradation have been studied using the nondestructive test methods of near infrared spectroscopy, CIELAB color measurement, visible-light spectroscopy, and Arrhenius time-temperature superposition. Arrhenius time-temperature superposition allowed analysis of near infrared and visible-light spectra, and color parameters to predict thermal degradation and color change of wood at 120-180celcius for 6 min to nine months duration. Two-dimensional correlation spectroscopy for the complementary analysis of near infrared and visible-light spectroscopy was applied to investigate chemical changes during wood thermal degradation that cause the observed color change. Visible-light spectroscopy with CIELAB color measurement was used to obtain information on color changes, and near infrared spectroscopy was applied in the measurement of chemical changes during thermal degradation. Changes in spectral intensities in 2D correlation spectroscopy indicated that different chemical components are responsible for color change during heat treatment and accelerated aging of wood. With dry-thermal treatment, the hemicellulose content decreased following a color change, whereas cellulose and lignin/extractives decreased with hygro-thermal treatment.

DOI： 10.1177/0967033519863878

Electrode polarization effects on interfacial kinetics of ionic liquid at graphite surface: An extended lagrangian-based constant potential molecular dynamics simulation study Reviewed

Inagaki Taichi, Nagaoka Masataka

JOURNAL OF COMPUTATIONAL CHEMISTRY Vol. 40 ( 24 ) page： 2131 - 2145 2019.9

Three-dimensional grain angle measurement of softwood (Hinoki cypress) using near infrared spatially and spectrally resolved imaging (NIR-SSRI) Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

HOLZFORSCHUNG Vol. 73 ( 9 ) page： 817 - 826 2019.9

Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

As the strength of wood is greatly affected by its three-dimensional (3D) grain angles (the dive angle and the surface angle), the wood industry today requires automatic, rapid, and robust measurement techniques for measuring them simultaneously. In the present study, a near infrared spatially and spectrally resolved imaging (NIR-SSRI) system was designed in a line scan model, mainly including an NIR hyperspectral imaging camera and a halogen spotlight source (empty set 1 mm). Spatially resolved diffuse reflectance images at three target wavelengths (1002 nm, 1217 nm, and 1413 nm) were obtained from Hinoki cypress [Chamaecyparis obtusa (Siebold & Zucc.) Endl.] samples at various (0 degrees, 3 degrees, 6 degrees, ... 45 degrees) dive angles and surface angles (0 degrees, 3 degrees, 6 degrees, ... 45 degrees). The scattering patterns caused by the "tracheid effect" were almost elliptical. Subsequently, nonlinear least squares fitting was used to determine their eccentricities (e) and rotation angles (theta). The e values at each selected wavelength were highly correlated with the dive angle reference values; and the global identification model developed using Gaussian process regression (GPR) under five-fold cross-validation (CV) reached a determination coefficient (r(2)) of 0.98 with a root mean square error (RMSE) of 2.2 degrees. On the other hand, local surface angle identification models developed using linear regression analysis achieved determination coefficients higher than 0.90 on r(2) and an RMSE of CV lower than 3.8 degrees when the dive angle was lower than 30 degrees.

DOI： 10.1515/hf-2018-0273

Determination of Dielectric Function of Water in THz Region in Wood Cell Wall Result in an Accurate Prediction of Moisture Content Reviewed

Han Wang, Tetsuya Inagaki, Ian D. Hartley, Satoru Tsuchikawa, Matthew Reid

JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES Vol. 40 ( 6 ) page： 673 - 687 2019.6

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

This report follows up previous work that presented a model for the simultaneous detection of moisture content and density of wood using Terahertz time-domain spectroscopy. A significant improvement in the prediction accuracy of the model is demonstrated by including a moisture content-dependent dielectric function for the water within the wood samples. Justification for using the dielectric function is presented, the prediction accuracy is quantified, and the results compared with prior work.

DOI： 10.1007/s10762-019-00594-0

A new approach based on a combination of capacitance and near-infrared spectroscopy for estimating the moisture content of timber Reviewed

Vu Thi Hong Tham, Tetsuya Inagaki, Satoru Tsuchikawa

WOOD SCIENCE AND TECHNOLOGY Vol. 53 ( 3 ) page： 579 - 599 2019.5

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The moisture content (MC) of wood influences its material properties. Determination of MC is essential in both the research and manufacturing fields. This study examined a nondestructive method for estimating MC rapidly and effectively. A capacitance sensor and a near-infrared (NIR) spectrometer were used to measure the MC of Japanese cedar and Japanese cypress timber. High-frequency capacitance (20MHz) and NIR spectral absorption (908-1676nm) data were collected for cross section and tangential section, as well as for the whole-sample average, in two MC ranges: from the green to the fiber saturation point (FSP) and from FSP to air-dried state. The results indicated that when standard error of prediction (SEP) is compared, the performance in [FSP to air-dried state] was better; when coefficient of determination in cross-validation (Rval2) and residual predictive deviation in cross-validation (RPDval) were compared, the performance in [Green to FSP] was better. Statistical analysis was performed using multiple linear regression and partial least squares. Combining capacitance and NIR absorbance at two wavelengths (Capacitance+NIR-MLR calibration) from the green to FSP was the best calibration yielding the most promising results: Rval2=0.96, SEP=5.20% and RPDval=4.97 on the cross section of samples. The results were higher than those of other calibrations in R-2 and SEP and RPD values. The NIR-PLS calibration performed better than others with quite good R-2, lower SEP and higher RPD in the MC range from FSP to air-dried state. The first calibration using only capacitance of wood was good in the first range of MC, but it is not good in the second range (R-2 under 0.5). Depending on the MC range, the performance of each calibration was different. In both MC ranges, the results on the cross section were higher than on the tangential section due to the anisotropic characteristics of wood material. From Capacitance+NIR-MLR calibration, the predicted models were developed using multiple linear regression and logarithmic regression. Results suggest the possibility of developing a new portable device combining a capacitance sensor and NIR spectroscopy to accurately predict the MC of wood.

DOI： 10.1007/s00226-019-01077-0

Near infrared estimation of concentration of ginsenosides in Asian ginseng Reviewed

Tetsuya Inagaki, Norihisa Katayama, Rae-Kwang Cho, Xijun Chen, Satoru Tsuchikawa

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 27 ( 2 ) page： 115 - 122 2019.4

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

In this study, the feasibility of near infrared reflectance spectroscopy for the quality evaluation of the main bioactive compounds, ginsenosides, in Panax ginseng was examined. Second derivative NIR spectra of standard reagents of ginsenoside Rg(1), Re, Rb-1, Rc, Rb-2 and Rd were used for analysis. Characteristic bands were observed at around 5250 cm(-1) in the spectra of ginsenoside Rg(1) group (including Rg(1) and Re); however, this was not to be observed on the spectra of ginsenoside Rb-1 group (including Rb-1, Rc, Rb-2 and Rd). PLS regression models were constructed of air-dry ginseng powder samples and ginsenoside content in ginsengs was determined by HPLC methods. The calibration models covered various types of ginseng (white ginseng, red ginseng and bleached ginseng) from various cultivated areas (Japan, China and Korea) and were well established for each kind of ginsenoside. It was shown that NIR spectroscopy can be used for the accurate prediction of ginsenoside.

DOI： 10.1177/0967033518814851

Rapid identification of wood species by near-infrared spatially resolved spectroscopy (NIR-SRS) based on hyperspectral imaging (HSI) Reviewed Open Access

Te Ma, Tetsuya Inagaki, Mayuka Ban, Satoru Tsuchikawa

HOLZFORSCHUNG Vol. 73 ( 4 ) page： 323 - 330 2019.4

Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

Conventional near-infrared (NIR) spectroscopy has shown its potential to separate wood species nonde-structively based on the aggregate effect of light absorption and scattering values. However, wood has an aligned microstructure, and there is a large refractive index (RI) mismatch between the wood cell wall substance (n approximate to 1.55) and the cell lumen (air approximate to 1.0, water approximate to 1.33). Light scattering is dominant over absorption (mu(s)' >> mu(a)) in wood, and this fact can be utilized for complex classification purposes. In this study, an NIR hyperspectral imaging (HSI) camera combined with one focused halogen light source (empty set 1 mm) was designed to evaluate the light scattering patterns of five softwood (SW) and 10 hardwood (HW) species in the wavelength range from 1002 to 2130 nm. Several parameters were combined to improve the data quality, such as image histogram plots of defined spaced bins (associated with diffuse reflectance values of light), variance calculation on the frequency (the number of pixels in each bin) of each histogram and the principal component analysis (PCA) of all the variance values at each wavelength. The identification accuracy of the quadratic discriminant analysis (QUA) under the five-fold cross-validation method was 94.1%, based on the first three principal component (PC) scores.

DOI： 10.1515/hf-2018-0128

DETERMINATION OF CAROTENOIDS AND DOBI CONTENT IN CRUDE PALM OIL BY SPECTROSCOPY TECHNIQUES: COMPARISON OF RAMAN AND FT-NIR SPECTROSCOPY Reviewed Open Access

Rayakorn Nokkaew, Vittaya Punsuvon, Tetsuya Inagaki, Satoru Tsuchikawa

INTERNATIONAL JOURNAL OF GEOMATE Vol. 16 ( 55 ) page： 92 - 98 2019.3

Language：English Publishing type：Research paper (scientific journal) Publisher：GEOMATE INT SOC

Crude palm oil (CPO) is a rich source of carotenoids which are a precursor of vitamin A as an important antioxidant. Carotenoids and Deterioration Of Bleachability Index (DOBI) are important factors to indicated quality of CPO. The conventional method for DOBI and carotenoids determination use UV-Vis spectrophotometry and HPLC, respectively which methods use solvents and spend time for analysis. This research interests Raman and FT-NIR spectroscopy for carotenoids and DOBI determination due to those techniques are an alternative technique for rapid measurement, non-destruction of material, and environmental suitability. The results indicated that Raman is better for determination than FT-NIR spectrometry. In Raman analysis, multiplicative scatter correction (MSC) and standard normal variate (SNV) treated methods were the best models for carotenoids and DOBI, respectively. The bands of carotenoids were at 1,100 and 1,500 cm(-1) wavenumber. Validation on carotenoids produced 0.94 of correlation coefficient (R), 0.88 of coefficient of determination (R-2), 40.65 ppm of root mean square error of prediction (RMSEP) and 3.25 of the ratio of standard error of prediction to standard deviation (RPD). The validation of DOBI produced 0.76 of R, 0.57 of R-2, 0.31 of RMSEP, 1.92 of RPD of 1.92. The limitation of carotenoids and DOBI determination using FT-NIR is having sufficient concentration of carotenoids for analysis. In addition, data for various samples regarding location, season, and oil palm species are important to build models for precise prediction.

DOI： 10.21660/2019.55.4813

Effect of knots and holes on the modulus of elasticity prediction and mapping of sugi (Cryptomeria japonica) veneer using near-infrared hyperspectral imaging (NIR-HSI) Reviewed Open Access

Imran Arra'd Sofianto, Tetsuya Inagaki, Te Ma, Satoru Tsuchikawa

HOLZFORSCHUNG Vol. 73 ( 3 ) page： 259 - 268 2019.3

Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

Naturally occurring knots reduce the mechanical strength of wood. Veneers from sugi (Cryptomeria japonica) served as research material to study the effect of knots and holes. Veneer samples were first subjected to a three-point bending test to obtain measured modulus of elasticity (MOE) values. Then, near-infrared (NIR) hyperspectral imaging (HSI) was used to construct a prediction model and map the predicted MOE values. This is the first attempt for MOE prediction from the entire veneer surface based on NIR-HSI technology, while the mathematical part relies on chemometrics and cross-validation partial least squares regression (CV-PLSR). Maps of MOE prediction values could distinguish between latewood (LW) and earlywood (EW), as well as between a sound knot and a dead knot.

DOI： 10.1515/hf-2018-0060

Non-destructive evaluation of wood stiffness and fiber coarseness, derived from SilviScan data, via near infrared hyperspectral imaging Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 26 ( 6 ) page： 398 - 405 2018.12

Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

Near infrared hyperspectral imaging combined with partial least squares regression analysis was used to evaluate wood stiffness (modulus of elasticity) and fiber coarseness. Five samples with normal wood and compression wood collected from two Japanese Cedar (Cryptomeria japonica) trees were analyzed. To achieve high reliability of the prediction values, a SilviScan system (X-ray densitometry, X-ray diffractometry, and optical microscopy) with the high spatial resolution was used for measuring reference data. The measurement interval for modulus of elasticity and fiber coarseness was 1 mm and 25 mu m, respectively. After spectral pre-treatment and key wavelengths selection, partial least squares analysis was applied to calibrate near infrared data to reference values. The determination coefficient (R-CV(2)) of modulus of elasticity was 0.66 with a root mean square error of cross validation (RMSECV) of 1.80 GPa. For the constructed fiber coarseness calibration model, R-CV(2) and RMSECV were 0.62 and 35.02 mu m/g, respectively. Finally, modulus of elasticity and fiber coarseness mapping results show detailed information (156 mu m/pixel) at the grown ring level. The differences among earlywood, latewood, and compression wood were all well identifiable.

DOI： 10.1177/0967033518808053

Inspection of Microfibril Angle of Sugi Wood by THz-TDS Reviewed

H. Wang, S. Tsuchikawa, T. Inagaki

International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz Vol. 2018-September 2018.10

Authorship：Last author,　Corresponding author Publishing type：Research paper (international conference proceedings)

Wood as a biological material has large differences in individual properties, and terahertz time-domain spectroscopy (THz-TDS) provide a new possibility for the wood products industry since THz exhibits high transparency to wood with big birefringence and diattenuation. By using the complex refractive index and absorption coefficient, THz is excepted to estimate important properties such as fiber orientation, microfibril angle (MFA) etc. simultaneously. In this study, sugi was used as sample because of its simple structure. Density and moisture content were predicted by using the real part of complex refractive index combined with absorption coefficient and showed a high correlation between measured and predicted values, prediction of MFA is still an ongoing mission.

DOI： 10.1109/IRMMW-THz.2018.8510303

Optical characteristics of Douglas fir at various densities, grain directions and thicknesses investigated by near-infrared spatially resolved spectroscopy (NIR-SRS) Reviewed

Te Ma, Gary Schajer, Tetsuya Inagaki, Zarin Pirouz, Satoru Tsuchikawa

HOLZFORSCHUNG Vol. 72 ( 9 ) page： 789 - 796 2018.9

Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

A near-infrared spatially resolved spectroscopy (NIR-SRS) system, also called the hyperspectral imaging system, was applied in a line scanning model combined with a concentrated halogen light source (empty set 1 mm), and spatially resolved reflectance images of Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] wood were obtained. The samples with various densities, grain directions and thicknesses were observed in the NIR range of 1000-1600 nm. Then, a nonlinear curve-fitting algorithm was applied based on the steady-state diffusion theory model to estimate the absorption coefficient (mu'(s)), and reduced scattering coefficients (mu(a)),( )both parallel and perpendicular to the grain direction at each measurement position. The absorption scattering coefficients at 1457 nm and two kinds of reduced scattering coefficients at 1002 nm were highly correlated with wood densities measured by an X-ray densitometer. The correlation coefficients were 0.953 and 0.987 for 3 mm and 5 mm samples, respectively, while three optical profiles were combined. It can be concluded that NIR-SRS is a fast and simple method for measuring the optical characteristics of softwood, although it has a non-homogeneous cellular structure. Sub-surface density and grain direction could be predicted with satisfactory accuracy based on a few key wavelengths without relying on multivariate statistical analysis.

DOI： 10.1515/hf-2017-0213

Determination of physical and chemical properties and degradation of archeological Japanese cypress wood from the Tohyamago area using near-infrared spectroscopy Reviewed Open Access

Tetsuya Inagaki, Hitoshi Yonenobu, Yuuki Asanuma, Satoru Tsuchikawa

JOURNAL OF WOOD SCIENCE Vol. 64 ( 4 ) page： 347 - 355 2018.8

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER JAPAN KK

Here, we evaluated the application of near-infrared (NIR) spectroscopy for estimating the degradation level of archeological wood samples from the Tohyamago area, the dendrochronological ages of which were also determined. The wood samples were radially cut from three logs obtained from the Tohyamago area. NIR reflectance spectra were measured from the tangential faces of air- and oven-dried wood samples using a Fourier transform NIR spectrophotometer. The second derivative spectra within the wavenumber range of 6400-5200 cm(-1), in which the effect of moisture content in wood is suspected to be insignificant, showed a characteristic behavior with age. By comparing the second derivative spectral change in our wood samples with that in wood degraded by aging, thermal treatment, fungal attack, and lightning reported in the literature, we found that the second derivative spectra of wood samples from one log was similar to those of wood degraded by hygro-thermal treatment, whereas those of wood samples from another log was similar to those of wood degraded by brown-rot fungi. The physical and chemical properties of archeological wood were well predicted using a combination of partial least square regression analysis and NIR spectroscopy.

DOI： 10.1007/s10086-018-1718-8

Noncontact evaluation of soluble solids content in apples by near-infrared hyperspectral imaging Reviewed

Te Ma, Xinze Li, Tetsuya Inagaki, Haoyu Yang, Satoru Tsuchikawa

JOURNAL OF FOOD ENGINEERING Vol. 224 page： 53 - 61 2018.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

Near-infrared (NIR) hyperspectral imaging was used to evaluate soluble solids content (SSC) in 'Fuji' apples [Malus sylvestris (L.) Mill. var. domestica (Borkh. Mansf.)]. Eighty 'Fuji' apples were analyzed by collecting four small block samples from each one (approximately 2.0 cm x 2.0 cm x 1.5 cm). Partial least squares (PLS) regression analysis was performed to determine the relation between SSC reference data and NIR spectral data measured from each sample. The cross-validation coefficient of determination (r(2)) between predicted and measured SSC values is 0.89 with a root mean squared error of cross-validation (RMSECV) of 0.55%. Then, we successfully mapped SSC at a high spatial resolution (375 mu m per pixel). In addition, the absorption and reduced scattering coefficients of the measured samples were determined based on a diffusion theory model. The absorption coefficients are positively correlated to the SSC values (chemical information), whereas water cored tissue content (physical information) causes a characteristic change in light scattering coefficients. The fitting results were validated by Monte Carlo simulation, and the light penetration depth in 'Fuji' apples was estimated to be around 033 cm at 1198 nm and 0.17 cm at 1450 nm, respectively. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jfoodeng.2017.12.028

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