木材（特征图象）的微机识别

通过对“微机辅助木材识别系统WIP-89”项目的发展和增补,在木材识别方式上有新的突破,即通过木才解剖图象,微机自动识别木材,现已解决针对树材中的早材至晚材,急变和渐变;阔叶树材中的环孔材、半环孔材和散孔材。     

WOODPRO木材解剖特征图象处理系统的开发

本文简要地介绍了WOODPRO木材解剖特征图象处理系统；并结合木材细胞图象特点，描述了计算机图象处理技术在FFT图谱构建、木材细胞几何参数测量等方面的应用。     

小波包分析在木材超声检测中的应用

小波包分解能够准确地把超声检测信号划分到不同的频带范围内，实现了不同频带范围内能量变化量的提取。试验说明缺陷试件的信号能量变化量在一些特定的频带内显示出显著的不同，为下一步应用神经网络等模式识别方法辨别试件缺陷类型提供了比较理想的特征向量。     

西江桂和清化桂木材解剖特征的比较分析

以9年生的西江桂(Cinnamomum cassia)和清化桂(Cinnamomum cassia var.macrophyll)人工林木材为研究对象,对其微观结构、木材纤维形态特征和组织比量进行测定分析。结果表明:西江桂木材的的纤维长度、纤维宽度、纤维腔径、双壁厚、长宽比、壁腔比、腔径比分别为894.00μm、24.63μm、16.67μm、7.97μm、36.30、0.48、0.68;清化桂木材的的纤维长度、纤维宽度、纤维腔径、双壁厚、长宽比、壁腔比、腔径比分别为953.67μm、22.37μm、14.40μm、7.97μm、42.65、0.55、0.64。西江桂的木材导管、轴向薄壁组织、木射线、木纤维比量分别为9%、13%、10%、68%;清化桂木材的导管、轴向薄壁组织、木射线、木纤维比量分别为10%、20%、10%、60%。西江桂和清化桂木材的微观构造极为相似;但木材纤维特征中纤维长度、腔径、长宽比、纤维宽度、轴向薄壁组织比量、木纤维比量差异均显著或极显著,其他特征没有显著差异。     

基于小波分析的木材干燥过程的声发射信号的去噪研究

指出了木材结构的各向异性导致了木材声发射信号的提取的困难性。小波分析作为信号和信息的处理工具由于其优越性已经被大家所认可,特别是在去噪方面,小波的多分辨分析、相关性、低墒性使其在去噪领域有着独特的优势。声发射技术是一种动态的无损检测技术,它不仅能对缺陷进行实时的动态监测,还能对发展趋势进行预测。     

木材干燥理论在木材加工技术中的应用分析

在木材加工技术中,木材干燥理论包括木材平衡含水率理论、木材传热理论、木材水分扩散理论以及木材干燥应力与应变理论。以上几大理论涉及到木材的干燥处理、加工、维护以及强度设计。木材干燥理论在木材加工中具有十分重大的意义。     

基于Daubechies小波基的木材声学振动信号分析与评价

针对音板木材振动信号分析不深入的问题,本研究基于小波包分析方法对木材振动信号进行分析,建立一种木材声学振动评价的新方法。利用多通道FFT分析仪获取泡桐木材的振动信号,基于Daubechies小波基函数对振动信号进行3层小波包分解与重构,得到了振动信号的特征值,将小波包变换后木材振动信号的特征值与传统方法测定的声学振动性能参数进行比较分析。研究结果表明:木材的振动信号能量主要集中在0～1 000 Hz,在传播的过程中能量衰减迅速;对振动信号进行时域分析时得出,木材的动态弹性模量随着峭度因子的增大而减小,随着峰值因子的增大而增大;基于Daubechies小波基的分析方法得到的振动信号特征值与声学振动参数之间具有显著的相关性,其中木材信号的特征能量率与木材声学振动参数动态弹性模量、声辐射品质常数以及声传播速度之间存在显著的正相关关系,与声阻抗以及对数衰减率的相关性及变化趋势之间有显著的负相关关系。研究表明,可以应用Daubechies小波对木材振动信号进行分析与评价,此方法为木材声学振动性能的客观评价提供了新思路。     

多尺度分形特征在木材内部缺陷检测中的应用

将数字图像处理与木材检测相结合,对获取的木材图像进行图像处理与分析,获取高质量的木材图像是提高木材检测准确性的重要手段。利用微光摄像机作为图像输入传感器,并最终以数字信号的形式储存在计算机当中。应用数字图像处理技术对采集到的原始图像进行预处理,提高图像的质量,便于后续处理。将预处理后的图像分割成若干个子区域,计算出每个子区域的多尺度分形特征值。实验结果显示,图像中背景部分与边缘部分多尺度分形特征值存在明显差别,可以提取奇异性较大的多尺度分形特征值,他们的集合即为木材缺陷的边缘。     

小波分析与人工神经网络在木质材举无损检测中的应用

介绍了小波变换和人工神经网络在无损检测中的工作原理，分析了小波变换处理非平稳信号提取特征值、人工神经网络进行模式识别的优点，并提出小波、人工神经网络以及松散型和紧致型小波神经网络在木质材料的无损检测中的应用。     

小波分析与人工神经网络在木质材料无损检测中的应用

介绍了小波变换和人工神经网络在无损检测中的工作原理,分析了小波变换处理非平稳信号提取特征值、人工神经网络进行模式识别的优点,并提出小波、人工神经网络以及松散型和紧致型小波神经网络在木质材料的无损检测中的应用。     

THE DETECTION OF THE BOUNDARY OF IMAGE OF WOODANATOMICAL STRUCTURE MOLECULAR

INTRODUCTIONWiththedevelopmentofcomputerandseniorthehnology,imagcprocessingtechnol-ogr-hasmadeagreetprogrssandbeenap-pliedtomedicalscience.mechanicalflawde-tection,industrialcontrol,geologicalprosPeCt-ing.archaeology,astronomy'chemisty.'Phys-icsctc.Eventhoughithasjustbeenappliedinwoodscicnceforashorttime'imopprocess-ingtechnologyshowabroadprosPeCts.Thesegmentationofimagepsdthecollcc-tionofimageboundaryisoncofthemostclas-sictasksforstUdyinimageproc6ksing,imagcanal}'sisandcomputcr\,ision.…     

Multiresolutional image analysis of wood and other materials

The gloss of wood is a unique texture compared to that of other materials. To express it quantitatively, two digital-image analyses were performed. One method was multiresolutional contrast analysis, which was the new method developed in this study. The other method was fractal image analysis. Twenty-four specimens, including solid woods, wood-plastic composites (WPCs), printed grains, and granites, were prepared. Digital images of specimens were obtained in five sizes and in two illuminant directions (perpendicular and parallel to the grain). The multiresolutional contrast values of perpendicular illuminated images were calculated and compared among specimens. The result of this quantitative analysis was that the gloss of wood was characterized by bright spots in a relatively small area. Using fractal analysis, the fractal dimension of a digital image was used as an index of brightness changes, not for expressing the self-similarity. These indices showed results similar to those of the multiresolutional contrast analysis.Part of this paper was presented at the 47th annual meeting of the Japan Wood Research Society in Kochi, April 1997     

林区木质剩余物合理利用的研究

随着经济和社会的发展，以及生态环境的恶化，如何有效利用森林资源，既能实现森林的可持续发展，又能满足生产生活所需，成为人们面临的紧迫问题。本文分析林区木质剩余物利用的意义，介绍现有的利用途径，指出林区木质剩余物利用的发展趋势、对策及措施，旨在合理利用林区木质剩余物，以实现资源与环境的和谐发展。     

Analysis of Wood Anatomy Characteristics by Fast Fourier Transfer Image Analysis

ApplicationofFFTCOlllpLlteril11ageprocessi11gisal1ex`tecI1noIog}'wI1ichmerges0ptics.electro11ics-cOI11l,uteral1dpatter11recog-[lition.ltI1asbeenappIiedt`ideI}intI1cresearcl1of`voodsciencebecauSeitl1asthepropertiesofI1igI1nleasIIri11gspeed.I1igl1precisio11…     

Evaluation of the arrangement of wood strands at the surface of OSB by image analysis

 The objective of this paper is to evaluate the arrangement of wood strands at the surface of oriented strand board (OSB) by image analysis. Two-dimensional image analysis enables the number of strands and the area of each strand to be computed. In addition, the fiber direction of each strand may be measured manually by recording the acute angle between the fiber direction and the longitudinal axis of the specimen. The image analysis results suggest the following: the average strand area is proportional to the reciprocal of the number of strands. Samples containing many smaller strands exhibit a larger variation in strand size. The average strand area does not correlate with the distribution of the strand area represented by the coefficient of variation. However, there is a reasonable correlation between the number of smaller strands in the range 0 to 1 cm² and the coefficient of variation of strand area. At low average fiber orientations, i.e. better orientation with the principal panel axis, there is smaller variability in orientation. The upper side and lower side of OSB exhibit a different relationship between average fiber orientation and strand area. The upper side of the specimens contains larger strands and exhibits better fiber orientation than the lower side. This is thought to be a function of the production process. The lower side strands fall on a smooth moving substrate, whereas the upper side strands fall on a stable substrate of strands. The number of strands is lower on the upper side of the OSB panel because small size strands tend to migrate to the lower side of the OSB during production. The small particles tend to be vibrated through the strand mat to the lower face before pressing. Received 29 March 1999     

Utilization of wood cell wall components

This article summarizes current utilizations of wood cell wall components in relation to biorefinery of woody biomass as a separation method of its constituents. Especially, utilization of isolated lignins, involving transformation and molding, are demonstrated with respect to productions of carbon fibers and their further functionalization, such as developments of activated carbon fibers and electrodes for second battery and electric double-layer capacitor.     

Utilization of digital image correlation in determining of both longitudinal shear moduli of wood at single torsion test

A sophisticated approach for the precise determination of both longitudinal shear moduli of wood at single test is introduced. The method is based on the combination of the torsion test inducing pure shear stresses in sample and an optical method providing the full-field strain data of such stress state. The proposed procedure of the longitudinal shear moduli determination consists of two main steps. In the first step, the apparent longitudinal shear modulus following the standardized procedure (EN 408+A1) was determined. Secondly, both longitudinal shear moduli were derived based on the apparent longitudinal shear modulus and the shear strain distribution on the radial and tangential sample surfaces. The wood of European beech (Fagus sylvatica L.) was used as material for the experiments. The exploratory analysis revealed the increasing difference between the longitudinal shear moduli determined in the longitudinal–radial plane and in the longitudinal–tangential plane as the total torsion angle increased as well as with the increase in the average torsion stiffness. Further, the longitudinal shear moduli and the torsional longitudinal shear strength did not correlate well. Therefore, they cannot be used in order to predict each other. Although such findings need more detailed studies, they should be taken into account when designing wood structures.     

Digital image analysis of radial shrinkage of fresh spruce (Picea abies L.) wood

Contact-free digital image analysis was performed of the radial shrinkage of fresh, fully saturated small spruce wood beams. An experimental test set-up was developed to ensure constant distance from the charge-coupled device camera to the sample surface as well as constant climate and light conditions during the whole experiment. Dimensional changes were observed immediately after the drying process began. An unexpected distinct effect could be observed which could not be explained by drying surface layers only. After a fast initial radial shrinkage a slowing down of the dimensional changes occurred at high mean moisture contents. A complete interruption of any dimensional changes followed. Finally, a recovery from shrinkage was even observed. It is assumed that strong negative pressure occurred in the fully saturated capillaries owing to dehydration which led to additional dimensional changes. As a consequence, the break of the water column and aeration in these capillaries finally resulted in a recovery period in the shrinkage rate due to the pressure release. After this effect, the dehydration was characterized by a phase of fast and almost linear shrinkage due to drying surface layers. Finally, the shrinkage slowed down to zero when reaching equilibrium moisture content.