Application of Time-of-Flight near Infrared Spectroscopy to Fruits—Permeability of Pulsed Laser Beam into Satsuma Mandarin, White Grapefruit and Fuji Apple

2008 ◽  
Vol 16 (2) ◽  
pp. 139-142 ◽  
Author(s):  
Yohei Kurata ◽  
Yuka Ikemoto ◽  
Satoru Tsuchikawa
2002 ◽  
Vol 127 (2) ◽  
pp. 303-308 ◽  
Author(s):  
Satoru Tsuchikawa ◽  
Sanae Kumada ◽  
Kinuyo Inoue ◽  
Rae-Kwang Cho

Time-of-flight near-infrared spectroscopy (TOF-NIRS) was used to investigate optical characteristics of water-cored tissue in `Fuji' apples [Malus sylvestris (L.) Mill. var. domestica (Borkh. Mansf.)]. The combined effects on the time resolved profiles of water core, laser beam wavelength, and detection position of transmitted light were investigated in detail. Attenuance of peak maxima (At), time delay of peak maxima (Δt), and variation of full width at half maximum (Δw) decreased gradually as water core increased. Water-cored tissue transmitted much more energy because of the filling of intercellular spaces with liquid, so that the light path time through a sample decreased. These parameters were also strongly dependent on detection position and wavelength of the laser beam. The substantial optical path length calculated from Δt at λ = 800 nm was 10 to 17 times, while that for λ = 900 nm varied from six to 11 times the distance of the diameter of the fruit. Results indicated the optimum optical parameter for detection of water core was Δt.


2013 ◽  
Vol 138 (3) ◽  
pp. 225-228 ◽  
Author(s):  
Yohei Kurata ◽  
Tomoe Tsuchida ◽  
Satoru Tsuchikawa

We proposed a technique combining time-of-flight (TOF) and near-infrared spectroscopy (NIRS), termed TOF-NIRS, capable of measuring the time-resolved profiles of near-infrared (NIR) light with nanosecond resolution. Analysis of the variation in time-resolved profiles was used to estimate soluble solids concentration (SSC) and acidity in grapefruit (Citrus paradisi), and the prediction accuracy was compared with the conventional NIR measurement device. In data processing, the cross-correlation function, which evaluated the similarity between the reference and transmitted beams, was introduced as an explanatory variable for partial least squares regression. TOF-NIRS predicted both SSC and acidity in grapefruit with higher precision than the conventional NIR measurement with respective r values of 0.72 and 0.85. Specifically, the superiority of TOF-NIRS was attributed to measurement time and prediction accuracy in determining acidity.


Holzforschung ◽  
2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Yohei Kurata ◽  
Takaaki Fujimoto ◽  
Satoru Tsuchikawa

Abstract A new optical measurement system, the main components of which are a diode-pumped solid state laser and avalanche photodiodes, was introduced to clarify the optical characteristics of wood from the viewpoint of time-of-flight near infrared spectroscopy. The sample thickness and the wavelength of input pulsed laser clearly influenced the transmitted time-resolved profile. The effective optical path length became 15 times longer than the sample thickness. The optical model based on the diffusion approximation to the radiative transfer equation proved to be useful for thick samples, which can be optically regarded as an ideal diffuser, although wood is a structural material with non-homogeneous cellular structure.


2003 ◽  
Vol 128 (3) ◽  
pp. 391-396 ◽  
Author(s):  
Satoru Tsuchikawa ◽  
Emiko Sakai ◽  
Kinuyo Inoue ◽  
Kumi Miyamoto

Time-of-flight near infrared spectroscopy (TOF-NIRS) was applied to the detection of sugar and acid content in Satuma mandarin (Citrus unshiu Marc). The combined effects on the time resolved profiles of soluble solids, free acids, laser beam wavelength, and detection position of transmitted light were investigated in detail. Attenuance of peak maxima (At) and time delay of peak maxima (Δt) increased as sugar content increased. However, these optical parameters decreased with increases in acid content. In the case of a model sample of a polyurethane block immersed in specified solutions, At and Δt decreased by adding sucrose or citric acid. These results suggested that time resolved profile was governed not only by the concentration of soluble solid or free acid but also by other inherent factors of a fruit; for example, an optical characteristic of tissue or difference in refractive index between the tissue substance and the liquid. Results indicated the optimum optical parameters for detection of sugar and acid content were At and Δt, respectively.


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