The laboratory analyzing the complex spectral information with theoretical equation, chemotrics and machine learning


  • Prof. Satoru Tsuchikawa [st3842@]

   Wood Engineering, Forest Product Science, Applied Optics, Agricrutural Engineering
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  • Lecturer Tetsuya Inagaki [inatetsu@]

   Wood Engineering, Applied Optics, Forest Product Science  
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  • Assistant. Te MA  [mate@]

   Wood Engineering, Applied Optics, Forest Product Science
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Natural resources such as wood materials and agricultural products play an extremely important role in our daily life. As people are different from each other, natural materials also have various “personalities”.
 Natural material formation is a complex process composing many biological events, which gives each material with different character. (For example, the variation in mechanical properties and sugar contents can be seen in wood materials and oranges, respectively). To satisfy consumer expectations, production and processing of those natural materials require highly efficient and non-destructive management method.
State of the art system engineering for Biological resources aims to develop non-destructive evaluation methods for wood materials and fruits by using near infrared light which has wavelengths that are longer than those of visible light, meaning that humans cannot see it.
Meanwhile, our research interests also include “precision machining of wood materials”, ” promoting plants growth through artificial controlled conditions ” and “new wood-plastic composites processing.”
 In the above areas, environmental impact can be reduced through the machinery of renewable resources processing, as well as online quality detection and other technologies. Seemingly contradictory concepts of mechanization and Agronomy have been combined effectively in our research, we will also serve as unique and continue our efforts on the research of renewable biomaterials.

The application of NIR spectroscopy for wooden materials. 

We are establishing robust calibration for chemical or physical properties in wood by NIR spectroscopy   
with combining other method or establishing new chemometric method 

key word: NIR spectroscopy, wood, archaeology, moisture content, density, heat treatment, plantation tree, mechanical property

Related publication:

  • S. Tsuchikawa, “A Review of Recent Near Infrared Research for Wood and Paper”, Applied Spectroscopy Review ,42, 43-71(2007)
  • T. Inagaki, Y. Asanuma, S. Tsuchikawa, “Selective Assessment of Duplex Heat-Treated Wood by Near-Infrared Spectroscopy with Principal Component and Kinetic Analyses”, Journal of Wood Science, 64, 6-15 (2018).
  • V. T. H. Tham, T, Inagaki, S. Tsuchikawa, “A novel combined application of capacitive method and near-infrared spectroscopy for predicting the density and moisture content of solid wood”, Wood Science and Technology, 52, 115-129 (2018).
  • T. Inagaki, H. Yonenobu, Y. Asanuma, S. Tsuchikawa, “Determination of physical and chemical properties and degradation of archeological Japanese cypress wood from the Tohyamago area using near-infrared spectroscopy”, Journal of Wood Science, 64, 347-355 (2018).
  • I. A. Sofianto, T, Inagaki, K. Kato, M. Itoh, S. Tsuchikawa, “Modulus of elasticity prediction model on sugi (Cryptomeria japonica) lumber using online near-infrared (NIR) spectroscopic system”, International Wood Products Journal, 8, 193-200 (2017).

The investigation of the light scattering in materials 

We are investigating the complex light scattering in samples by time-resolved or spatially resolved spectroscopy with radiative transfer theory.
Based on the knowledge acquired from these research, we are developing new cheap and hand-hold devices

key word: Reduced scattering coefficient, time-resolved, spatially resolved, radiative transfer theory, mis-mach effect of index refraction, TFDRS (three fiber diffuse reflectance spectroscopy) 

Related publication:

  • M. Ban, T, Inagaki, T. Ma, S. Tsuchikawa, “Effect of cellular structure on the optical properties of wood”, Journal of Near Infrared Spectroscopy, 26, 53-60 (2018).
  • T. Ma, G. Schajer, Z. Pirouz, T. Inagaki, S. Tsuchikawa, “Optical characteristics of Douglas fir at various densities, grain directions, and thicknesses investigated by Near-Infrared Spatially Resolved Spectroscopy (NIR-SRS)”, Holzforschung, 72, 789-796 (2018).
  • T. Ma, T. Inagaki, M. Ban, S. Tsuchikawa, “Rapid identification of wood species by near infrared spatially-resolved spectroscopy (NIR-SRS) based on hyperspectral imaging (HSI)”, Holzforschung, 73, 323-330(2018).
  • R. Kitamura, T. Inagaki, S. Tsuchikawa, “Determination of true optical absorption and scattering coefficient of wooden cell wall substance by time-of-flight near infrared spectroscopy”, Optic Express, 24, 3999-4009, (2016).
  • K. Konagaya, T. Inagaki, R. Kitamura, S. Tsuchikawa, “Optical properties of drying wood studied by time-resolved near-infrared spectroscopy”, Optic Express, 24, 9561-9573, (2016).
  • T. Inagaki, D. Nozawa, Y. Shimomura, S. Tsuchikawa, “Three fiber-based diffuse reflectance spectroscopy for estimation of total solid content in natural rubber latex”, Journal of Near Infrared Spectroscopy, 24, 327-335 (2016).

The imaging analysis of NIR hyper spectral imaging 

We built robust calibration for NIR hyper spectra imaging data with chemometrics and machine learning
and recognize it with deeplearning like CNN.

key word: Hyper spectral imaging, machine-learning, chemometrics, deep learning, CNN(convolutional neural network)

Related publication:

  • H. Kanayama, T. Ma, S. Tsuchikawa, T. Inagaki, “Cognitive spectroscopy for wood species identification: Near infrared hyperspectral imaging combined with convolutional neural network”, Analyst 144,6438-6446 (DOI: 10.1039/C9AN01180C
  • T. Ma, X. Li, T. Inagaki, H. Yang, S. Tsuchikawa, “Noncontact Evaluation of Soluble Solids Content in Apples by Near-Infrared Hyperspectral Imaging”, Journal of Food Engineering, 224, 53-61 (2018).
  • T. Ma, T. Inagaki, S. Tsuchikawa, “Calibration of SilviScan data of Cryptomeria japonica wood concerning density and microfibril angles with NIR hyperspectral imaging with high spatial resolution”, Holzforschung, 71, 341-347 (2017).
  • H. Yang, T. Inagaki, T. Ma, S. Tsuchikawa, “High-Resolution and Non-destructive Evaluation of the Spatial Distribution of Nitrate and Its Dynamics in Spinach (Spinacia oleracea L.) Leaves by Near-Infrared Hyperspectral Imaging”, frontiers in Plant Science, 8, 1937 (2017).

Thz evaluation of wood materials

We are establishing new method using THz spectroscopy for properties (crystalline structure, moisture content, density, fiber orientation) in engineering wood!

KEY WORD: THz time domain spectroscopy, effective medium theory, cellulose crystalline structure, MFA


  • H. Wang, T. Inagaki, I. D. Hartley, S. Tsuchikawa, M. Reid, “Determination of dielectric function of water in THz region in wood cell wall result in an accurate prediction of moisture content”, International Journal of Infrared and Millimeter Waves,40,6,673-687(2019)
  • T. Inagaki, B. Ahmed, I.D. Hartley, S. Tsuchikawa S. and M. Reid, “Simultaneous Prediction of Density and Moisture Content of Wood by Terahertz Time Domain Spectroscopy”, Journal of Infrared Millimeter and Terahertz Wave, 35, 949-961 (2014)
  • T. Inagaki, I.D. Hartley, S. Tsuchikawa and M. Reid, “Prediction of Oven-dry Density of Wood by Time-domain Terahertz Spectroscopy”, Holzforschung, 68, 61-68 (2014).


Graduate School of Bioagricultural Science, Nagoya-university
System Engineering for Biological Resources

〒464-8601 Furo-cho, Chikusa-ku, Nagoya city, Japan

Higashiyama Campus
From Nagoya Station:
Take the subway Higashiyama Line to Motoyama Sta. (15minutes).
then transfer to the Subway Meijo Line to Nagoya Daigaku Sta. (Higashiyama Campus is just off the subway exit.)

From Centrair (Central Japan Internatinal Airport):
Take the Meitetsu Line to Kanayama Sta. (30min.),
then transfer to the Subway Meijyo Line to Nagoya Daigaku Sat. (21min.)