数学形态学与Canny算子在木材腐朽图像特征提取中的应用

根据数学形态学和边缘检测算子以及木材腐朽图像的特征,选择多尺度多结构的形态学算法,首先对图像进行交替顺序多尺度结构元素的膨胀、腐蚀滤波;再用多结构元素对图像进行开闭运算达到去除噪声,保留图像细节的目的;最后利用Canny算子提取图像的边缘特征。实验结果表明该方法抗噪能力强,能有效提取图像的边缘特征。     

基于图像处理的木粉目数检测与分析

为了解决生产中木粉目数传统检测方法存在的问题,结合先进的数字图像处理技术,在分析木粉颗粒形态特征的基础上,提出了一种基于形态学边缘检测和最大Feret直径的目数检测方法。该方法首先进行图像HIS颜色空间转换,基于S分量进行目标提取,应用多尺度形态学边缘检测算子提取边缘,然后根据颗粒形态特征只保留Feret最大方向上的直径,最后通过单位换算实现目数检测。实验结果表明,该方法具有较高的检测精度,可在生产中推广应用。     

我国木材进口分析

中国是世界上木材及木制品的生产大国,也是消费大国,又是木材进口大国,我国木材进口贸易充满了机会和挑战。通过具体分析近年我国原木、锯材、胶合板进口的品种、数量和贸易方式的变化,把握未来的发展趋势,木材经营企业一方面要关注全球木材贸易走向,快速反应,坚持多品种,小批量的经营原则。同时,还应该积极实施走出去战略,建立稳定资源渠道,占领木材进口市场竞争制高点。     

Factors influencing steel tool wear when milling wood

The wear of high speed steel cutting tools after milling wood of four selected wood species was studied. For the experiments wood specimens were chosen with very different silica contamination, wood density, and high temperature corrosivity (HTC) of wood towards tool material. Analyses performed show that the silica content and wood density display poor linear correlation with the cutting tools wear, while the correlation of the HTC appeared very good. The silica contamination and the HTC effects overshadow each other. Thus, a theoretical multivariable simulation of the cutting edge wearing process, employing all experimental variables, was applied, providing a very good explanation of the analyzed problem.     

THE EFFECT OF RAINFALL ON THE LATE WOOD OF SCOTS PINE AND OTHER CONIFERS IN EAST ANGLIA

In Scots pine (Pinus silvestris L.) near Oxford, early woodwas found to start growing at about the beginning of April,late wood at about the beginning of July, and growth ceasesat about the end of August. Five late wood types were distinguishedin pine growing under the "continental" climatic conditionsof East Anglia. These types appear to be related to rainfalldistribution. The sharpness of the inner edge of the late wooddepends upon the availability of water at the end of early woodformation, a dry spell causing a sharp distinction. Wet conditionsin the middle of late wood formation may cause a zone of lessdense tissue, but this is rare.     

形态学双梯度算子在木材腐朽图像边缘检测中的应用

根据数学形态学的思想和木材图像的特性,选取适当的结构元素,通过腐蚀、膨胀、开与闭运算的加权组合,构造出形态学双梯度算法,并将它应用于木材腐朽图像的边缘检测。通过与经典边缘检测算法对比,该方法提取的图像边缘更加的准确、完整和连续;显现出更好的抗噪声能力和边缘检测能力,实验结果验证了该方法的可行性与有效性。     

General laws of wood deformation and rheological propertions of hardwood

Summary Characteristic features of wood deformation under loading at changing moisture contents (temperature) are discussed on the basis of results from rheological tests with hardwood. General laws of deformation in wood as a result of various cyclic effects of loading as well as of temperature and moisture content have been established. These laws have been used to solve the problem of the plane stress state in lumber when dried by using the method of finite elements. To control internal stresses and for an effective drying process, it is suggested that differential shrinkage should be measured, i.e. the difference between the displacements of points on Both verges of the board's edge and in the centre of the edge.Presented at the Meeting of the European-African Group of IAWS with the topic Structure and Utilization of hardwoods, Banska Bystrica, CSSR, September 9–11, 1975.     

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。     

Characterization of cellulose in compression and opposite woods of a Pinus densiflora tree grown under the influence of strong wind

Summary Structural factors in a Pinus densiflora tree grown under the influence of strong wind were measured. No difference for cellulose molecules was noticed between compression and opposite wood, but the was somewhat lower in the region where the compression wood was concentrated. The degree of crystallinity of cellulose was 45–50% in compression wood, about 50% in normal wood, and 50–60% in opposite wood. The crystallinity decreased with increasing height above the ground. The maximum point of crystallographic b-axis (fiber axis) orientation distribution for cellulose crystallites in compression wood was located at 30°, in normal wood at 25° and in opposite wood at 0°. The cellulose crystallite dimension in the transverse direction was 3.2 nm, corresponding to four cellulose unit cells, a value that was almost constant throughout the wood. In the longitudinal direction, there were large differences in cellulose crystallite dimensions between compression and opposite woods. In compression wood the cellulose crystallite dimensions was 12 nm corresponding to 11–12 cellulose unit cells. In opposite wood it was 17–32.5 nm corresponding to 17–32 cellulose unit cells. These structural factors were apparently affected by the environmental conditions, and the mechanical properties of the wood were influenced by these factors. Opposite wood had longer crystallites, a higher degree of crystallinity and a better orientation distribution of cellulose crystallites in the longitudinal direction. Compression wood, on the other hand, had shorter crystallites, a lower degree of crystallinity and a large angle between the stem and the direction of the crystallites.     

基于形态学梯度算法的木材缺陷图像边缘检测

根据形态学梯度算法的思想,选取平坦的菱形为结构元素,通过腐蚀、膨胀、开与闭运算的加权组合,构造出一种形态学优化算法,并将它应用于木材缺陷图像的边缘检测中,使提取的图像边缘更加准确、完整和连续.通过与经典边缘检测算法对比,该方法有更好的抗噪能力和边缘检测能力,实验结果也验证了该方法的可行性与有效性.     

Proximity to the forest edge affects the production of sexual offspring and colony survival in the red wood ant Formica aquilonia in forest clear-cuts

Abstract

Red wood ants of the Formica rufa group, as well as their nests, form a vital part of the ecosystems of both European and Siberian boreal and temperate forests. It has been well documented that the nests of red wood ants in clear-cuts do not perform as well as those deeper in the forest. However, clear-cuts may not be a homogeneously poor habitat for such forest-dwelling ants because the distance of the nest site to the edge of the remaining forest may be a significant factor affecting the nest performance. In this study, I compared the probability of nest survival and sexual offspring production between the nests of Formica aquilonia (Yarrow, 1955) in a forest edge zone (distance to the forest edge <9.2 m) and a clear-cut centre zone in 18 different clear-cut areas. Although the nests were generally smaller, the probability of sexual offspring production and nest survival was higher among those nests in the edge compared to the centre zone. Since the proximity to the forest edge increased the performance of a nest, selective logging and smaller scale clear-cuts may not be as harmful to red wood ants as clear-cutting over a large area.     

Shear resistance and failure modes of nailed joints loaded perpendicular to the grain

Shear tests were conducted on nailed joints in wood that were loaded perpendicular to the grain; these joints had 21 specifications depending on different combinations of wood species, nail dimensions, number of nails, and edge distances of the main members, and their effects on the shear resistance of the nailed joints were also investigated. The nailed joints with CN75 nails had higher initial stiffness than the joints with CN50 nails, provided the initial stiffness of nailed joints connected with 3 or 5 nails was not always a simple product of the number of nails and the initial stiffness of nailed joints connected with a nail, and instead depended on the combination of wood species of the main member and nail dimensions. When the edge distance decreased, the maximum load and energy capacity decreased, thereby affecting the energy capacity. The maximum load of the nailed joints with CN75 nails may be smaller than those with CN50 nails depending on the combination of wood species and nail dimensions. When the edge distance of the nailed joints was less than 26 mm, the energy capacity of the nailed joints with CN75 nails was less than or similar to those with CN50 nails.     

木材CT图像的三维重构

运用CT技术对木材进行无损检测,运用多重分型频谱技术可以对木材CT图像进行有效的边缘检测.针对木材CT图像低对比度、原木缺陷边缘提取困难等问题,采用多重分型频谱技术对处理后的图像进行提取,提取的边缘信息清晰完整、准确度较高,为后续的木材CT图像的三维重建提供有效信息.使用线性插值法对木材CT图像进行三维重建,该方法具有便于理解、实现简单和运算速度快的特点.所运用的线性插值法对木材CT图像三维重建的过程有较好重建效果,具有重建图像直观、清晰的优点,这种重建理论为提高木材利用效率和原木的虚拟切割提供了一种有效的思路.     

Preparation and Characterization of the Phenolated Wood Using Sulfuric Acid as a Catalyst Ⅱ. FT-IR and GPC Characterization

By means of gel permeation chromatography analysis, the molecular weight of liquefied wood under different reaction conditions was investigated to trace the change in the structural characteristics of the liquefied wood. The insoluble residues were analyzed by Fourier transform infrared to investigate the liquefaction order of three main wood components. The results indicate that both reaction temperature and reaction time could affect the molecular characteristics of the liquefied wood obtained. The molecular weight of liquefied Chinese Fir wood is higher than that of liquefied Poplar wood under most of reaction conditions. During wood liquefaction, lignin is liquefied firstly. Hemicellulose is liquefied in the middle stage and cellulose is the most difficult to be liquefied.     

Saproxylic beetles in high stumps and residual downed wood on clear-cuts and in forest edges

Abstract

This study evaluates how the placement and the different possible outcomes of a spruce retention tree affected species richness and assemblages of spruce-associated saproxylic beetles. In a field experiment in the boreal zone of central Norway, high stumps were created and compared with residual wood pieces (i.e. top boles with branches), in clear-cuts versus in forest edges. Flight interception traps were mounted close to the substrate. The results were analysed using rarefaction techniques, ordination (DCA) and anova. It was found that the placement of retention trees of spruce does matter: beetle assemblages were significantly different in stumps in the four treatments. For all species pooled, the species richness was higher in stumps in clear-cuts than in stumps or boles in the forest edge. Four red-listed species were more abundant near stumps than boles, and two red-listed species were more abundant in clear-cuts than forest edge. To cater for the variety of habitat preferences among forest beetles in managed forest, managers should leave both standing spruce trees (many of which will end up as windthrown, downed boles) and some high stumps (to secure some upright dead wood), in both exposed clear-cut and semi-shaded forest edge.     

Applying multifractal spectrum combined with fractal discrete Brownian motion model to wood defects recognition

Wood nondestructive testing technology is a new and multidisciplinary industry scientific research. It has attained fast development and achievements in recent years. X-ray computed tomography (CT) scanning technology is a kind of wood nondestructive testing technology in practice. CT scanning technology has been applied to the detection of internal defects in the logs for the purpose of obtaining prior information, which can be used to reach better wood sawing decision. Fractal geometry and its extension multifractal are used for describing, modeling, analyzing, and processing of different complex shapes and images. A method in CT image edge detection using multifractal theory combined with fractal Brownian motion is applied in the paper. First, its multifractal spectrum is estimated. Then, different types of pixels are classified by the spectrum; they are smoothing edge points and singular edge points. From the images processed by multifractal spectrum theory and compared with each image by different spectrum values, it can be seen that the larger the range of threshold is set, the more exact the edge can be detected. The paper provides a new method to recognize the defect information and to saw it in the condition of nondestructive wood.     

基于数字图像处理技术实现木材横纹压缩过程中构造学形态特征的研究

根据计算机视觉技术,结合横纹压缩木材构造形态特征,提出了适合于木材横纹压缩过程中构造形态特征的图像处理方法。对图像质量的完善较全面地进行了量化,充分表露出计算机视觉技术在实现木材横纹压缩过程中构造学形态特征动态变化分析中的优越性,实现了木材细胞边缘轮廓的跟踪,形态特征的提取,为木材科学的再发展奠定了理论基础。     

Reactivity of wood charcoal with ozone

We investigated the resistance of wood charcoal against ozone and estimated the half-life of the charcoal in air. The weight of wood charcoal prepared by the carbonization of Fagus crenata sawdust at 400°C (C-400) was not affected with up to 8.5% ozone while the charcoal prepared at 1000°C (C-1000) burned with 4.9% ozone. Pores with a diameter of approximately 100–200nm were observed on the surface of ozone-treated C-1000 by scanning electron microscopy, although no pores were found in ozone-treated C-400. The peak positions of the C1s spectra and the full width at half maximum of X-ray photoelectron spectrum peaks suggest that C-400 has an amorphous structure composed of aliphatic carbons and small aromatic molecules while C-1000 and activated charcoal (AC) are polyaromatic. It is likely that the aromatic layers of C-1000 and AC were destroyed and the edge carbon atoms were removed as CO or CO₂ by ozone oxidation. We estimated the half-life of C-1000 with ozone in air to be about 50000 years by assuming that the weight of C-1000 decayed exponentially. Thus, it is suggested that wood charcoal is stable on a geological time scale.     

The influence of technical characteristics of wood milling tools on its wear performance

Influence of technical and chemical characteristics of industrial wood milling tools on its wear was analysed. Four tools of different manufacturers were subjected to the research. Lithuanian oak wood was chosen for the research as a reference material. Behaviour of cutting tools was assessed on the adopted industrial thickness planer SR3-6 with cutting speed of 31 m/s. Wear performance was evaluated on milling the specimens until 3200 m of true cutting length. Summarising achieved results, the following can be stated: chemical composition of tool and heat treatment schedule has great impact on the tool edge wear. The highest wear resistance was reached on testing tools made of CT01M-LA2; tools made of high-alloyed tool steel 8X6HΦT have presented the highest cutting edge radius and edge recession in each type of test as compared with tools made of high-speed tool steels Z80WCV18-04-01/18-0-1 and HS18-0-1, respectively. All these tools are suitable for oak wood processing. The high-alloyed tool steel shows similar wear performance as high-speed tool steels.     

基于分水岭算法的木材缺陷边缘检测

获取边缘图像的一种典型方法是利用梯度算法作用于图像,然后对得到的梯度图像做阈值处理,从而得到二值边缘图像.这种方法的缺点是很难选取适当的阈值.如果阈值选得太低,不但会产生假的边缘,而且得到的边缘很厚,必须做细化处理,而细化后的边缘位置往往不是很精确;如果阈值取得太高,许多边缘可能检测不到,或边缘出现过多的断裂部分.