Abstract
Wood has the unique gloss property originated in its anatomical structures. The objective of this study is to characterize such gloss property quantitatively by using image analyses. Smooth radial surfaces (edge grain) with various grain angles of Japanese cypress (Chamaecyparis obtusa) were finished with a microtome. A series of the surface images of the specimen was taken by a digital still camera while changing the incident angle by 5° in the range from 0° to 70°. Lightness values of the surfaces were calculated by the image analysis, and was compared to glossiness measured by a glossmeter. Two profiles of the relation between the incident angle and the lightness and the relation between the incident angle and the glossiness were similar very much. The image analysis also could elucidate the gloss property of the wood surface with the grain angle as like as goniophotometry by the glossmeter. Furthermore, the surface images were captured by a flat-bed scanner and an epi-illumination type microscope. A ratio of the latewood in the surface and a ratio of cell wall section in the small earlywood or latewood area were computed using the scanned image and the microscopic image, respectively. Combining both ratios, a total ratio of the cell wall section in the surface was estimated. The specular glossiness of the surface tended to depend on the amount of the smooth section of cell walls.
