Bucur V
Centre de Recherches Forestières de Nancy, INRA, Laboratoire d'Etudes et Recherches sur le Matériau Bois, LERMAB UMR 1094, 54280 Champenoux, France.
Ultrasonics. 2005 Feb;43(4):237-9. doi: 10.1016/j.ultras.2004.06.008.
The aim of this study is to assess wood quality of standing trees with ultrasonic velocity methods. The ultrasonic techniques currently used are: scattering based techniques that use travel time and other wave parameters for measuring the elastic constants of wood, and ultrasonic tomographic imaging techniques which seek to provide a high resolution picture of the defect. Scattering based techniques were firstly used as nondestructive techniques with increment cores of 5 mm diameter. On these specimens measurements with bulk waves--longitudinal and shear were used to detect the influence of sylvicultural treatment (pruning) on wood quality and also to detect defects (slope of grain, wavy figures). High resolution imaging techniques were developed for imaging abnormalities induced by biological attacks of fungi or insects in standing trees. In this case, ultrasonic tomography refers to cross-sectional imaging of trees from data collected by illuminating the tree from different directions. Ultrasonic images were reconstructed from the time of flight. The images were reconstructed from 120 measurements in situ and through the bark with direct transmission technique, using 1 MHz transducers. The resolution is 5 cm.
本研究的目的是用超声波速度法评估立木的木材质量。目前使用的超声技术有：基于散射的技术，利用传播时间和其他波参数来测量木材的弹性常数；以及超声层析成像技术，旨在提供缺陷的高分辨率图像。基于散射的技术最初被用作无损检测技术，使用直径为5毫米的生长锥芯。在这些样本上，利用体波（纵波和横波）测量来检测造林处理（修剪）对木材质量的影响，以及检测缺陷（纹理斜率、波浪状纹理）。高分辨率成像技术被用于对立木中由真菌或昆虫的生物侵害引起的异常情况进行成像。在这种情况下，超声层析成像指的是通过从不同方向照射树木收集的数据来进行树木的横截面成像。超声图像根据飞行时间重建。这些图像是使用1兆赫兹换能器，通过直接传输技术在原地并穿透树皮进行120次测量后重建的。分辨率为5厘米。
