Directional Characteristics of near Infrared Light in the Process of Radiation and Transmission from Wood

Abstract

In this report, a newly designed apparatus, that is, a near infrared auto-goniophotometer, was introduced to acquire detailed optical information about biological material having a cellular structure like wood. Such information allows us to analyse the three-dimensional physical condition of a sample and confirm the suitability of proposed optical models. The directional characteristics could be found on the basis of the intensity of reflected or transmitted light at each observation angle. In these experiments, Sitka spruce (Picea sitchensis Carr.) with various thicknesses were used. Results of these measurements showed the directional characteristics which were affected significantly by the illumination conditions and sample thickness. Particularly, these varied characteristically with the wavelength of the incident light. This result supports the validity of the proposed optical models which vary with wavelength. Throughout these analyses, the relationships between the physical aspects of a sample and the emitted light from it is being clarified.

The Relationship between near Infrared Spectra of Radial Wood Surfaces and Wood Mechanical Properties

“…19,20 In addition to the sensitivity of NIR spectra to changes in the chemical composition of wood, absorbance in the NIR range is also subject to the influence of concentration/ density 21,22 and variations in the cellular structure of wood. 23,24 A strong correlation between NIR spectra and compressive strength was achieved by Hoffmeyer and Pedersen. 11 To prove that the prediction of strength is not only based on the influence that density exerts on NIR absorbance, they subjected wood samples of equal density to progressive chemical degradation.…”

FT-NIR spectroscopy in predicting the decay resistance related characteristics of solid Scots pine (Pinus sylvestris L.) heartwood

“…Combined with multivariate data analysis techniques, NIRS is used widely for the determination of physical and chemical properties of solid wood (Burns and Ciurczak 1992;Tsuchikawa et al 1996Tsuchikawa et al , 1998Schimleck et al 1997Schimleck et al , 2005Gindl et al 2001;Kelley et al 2004;Poke et al 2004;So et al 2004;Jones et al 2006). Combined with multivariate data analysis techniques, NIRS is used widely for the determination of physical and chemical properties of solid wood (Burns and Ciurczak 1992;Tsuchikawa et al 1996Tsuchikawa et al , 1998Schimleck et al 1997Schimleck et al , 2005Gindl et al 2001;Kelley et al 2004;Poke et al 2004;So et al 2004;Jones et al 2006).…”

A survey of moisture distribution in two sets of Scots pine logs by NIR-spectroscopy

“…For instance, commercial moisture meters based on NIR are widespread. Even structural properties belong to them (Hoffmeyer and Pedersen 1995;Schimleck et al 2001), and Tsuchikawa (1998a) and Tsuchikawa et al (1998bTsuchikawa et al ( , 2001 also studied this area. By means of NIRS, apparently very different properties of wood can be detected (Gindl et al 2001;Schimleck and Evans 2004).…”