Directional Characteristics of Near Infrared Light Reflected from Wood
Directional Characteristics of Near Infrared Light Reflected from Wood
复制标题
木材反射近红外光的方向特性
DOI：
10.1515/hf.2001.086
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发表时间：
2001
影响因子：
2
通讯作者：
S. Tsutsumi
中科院分区：
文献类型：
--
作者：
S. Tsuchikawa;M. Torii;S. Tsutsumi
摘要设计了一种近红外自视光计，用于获取具有细胞结构的生物材料（如木材）的光学特性的详细信息。由偏振光照射近红外光产生的反射光，利用两个偏振光滤光片将其分离为非偏振光和偏振光。测量了各组分在不同入射角θ和观测角η、ρup （θ, η）和ρp （θ, η）下的标准化反射强度。采用不同厚度的锡特卡云杉样品。测量结果表明，辐照条件和样品厚度对非极化组分的定向特性有显著影响。特别是，这些随入射光的波长λ而变化。这表明我们之前提出的定向特性模型是合理的。另一方面，偏振分量的方向特性矩阵通常呈椭圆形，受入射角的影响很大，λ的影响很小。在此基础上，确定了样品厚度对光谱方向特性的影响。
Summary A near infrared auto-goniophotometer was designed to acquire detailed information on optical characteristics of a biological material which had a cellular structure, such as wood. The reflected light, which originated from the irradiation of polarized near infrared light, was separated into an unpolarized and a polarized component by using two polarizing filters. The standardized reflected intensities of each component at various incident angles θ and observation angles η, ρup (θ, η) and ρp (θ, η), were measured. Sitka spruce samples with various thicknesses were used. The measurements showed that the directional characteristics of the unpolarized component were affected significantly by the irradiation conditions and the sample thickness. Particularly, these varied with the wavelength of incident light λ. This shows that the directional characteristics models we proposed previously are reasonable. On the other hand, matrices of the directional characteristics for polarized components typically show an elliptical shape which is strongly affected by incident angle and only slightly by λ. Based on these results, the effects of sample thickness on the spectral directional characteristics were determined.