Locating and identifying splits and holes on sugi by the laser displacement sensor

The split and the hole are two common defects on sugi (Cryptomeria japonica D.Don). They have a common feature in that they are associated with surface irregularities. We have developed a laser scanning system to detect the splits and the holes based on their thickness, which correlates spatially with the profile information. The displacements measured by the laser sensor were converted to pixel values to generate the displacement profile image. Both the splits and the holes manifested well in the image. A dedicated image-processing program written in Visual Basic has been developed. The defects regions were accurately located by the image processing. To identify the defects, eight recognition rules based on four features have been utilized. Furthermore, a method based on the pixel model was proposed to compute the area of the defect. The results indicated that the defects could be identified correctly, and the areas could be computed accurately using the pixels model.     

Evaluation of surface smoothness by laser displacement sensor 1: effect of wood species

The best methods for determining surface roughness in an industrial environment are of the noncontact variety, with reproduction of the profile. The objective of this work was to compare the roughness profile obtained by a contact stylus with a commercial laser displacement sensor (LDS). Measurements were done using 15 wood species with different densities and colors, based on which special triangle profiles were prepared. The accuracy of the laser sensor was examined by statistical analysis of roughness parameters measured from the profiles. Experimental results show that LDS profiles were imitated correctly. However, LDS accuracy depends on the scanned wood properties (density and color), installation position of the sensor, and profile shape. It was found that evaluation of dark and high-density wooden surfaces was imperfect.Part of this work was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000; and at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001     

竹炭孔隙性状的探索

将竹炭横切面与纵切面的扫描电镜照片放入计算机进行处理,得到竹炭两个切面的轮廓图像和二值化图像.运用Autocad软件,观察到竹炭孔隙形状极不规则,为曲线型,孔隙表面为非平滑表面.依据分形理论,竹炭孔隙非平滑表面具有分形特征,以盒计数法测定竹炭孔隙表面分形维数D =2.2723.对竹炭两切面的二值化图像进行像素扫描,计算出竹炭横切面孔隙率为56.26％,纵切面孔隙率为62.37％.以直观图像为研究对象,得到竹炭孔隙的基本特征,对表征孔隙结构有一定参考价值.     

边缘阴影和晕圈对基于图像叶面积测量的影响及修正

叶片边缘阴影和晕圈对基于图像树叶面积测量精度有较大的影响。分析了边缘阴影和晕圈产生的原因,并提出了修正方法。首先将图像由RGB模式转换为Lab模式,基于a,b分量用自适应动态区域生长方法提取粗略的叶片图像。然后用膨胀和腐蚀形态学方法对区域生长结果进行处理,分割出确切的叶片的区域,背景区域和未知区域。最后用改进的马尔可夫随机场方法对未知区域像素进行判断并归类到叶片区域或背景区域。该方法可极大提高叶面积测量的精度。     

Nondestructive measurement of cross-sectional shape of a tree trunk

To evaluate windthrow resistance with respect to stem breakage, a nondestructive method for determining the shape of trunk cross sections was developed. In this method, the coordinates of multiple gauge points set on the perimeter of a trunk are calculated by measuring the distances between them. The shape between the gauge points is generated with the use of a profile gauge placed between them. Measurement tests were conducted using profile gauges with lengths of 300 and 900 mm on model specimens with four shape patterns and four different diameters. The accuracy of the estimation was verified by comparing the section modulus calculated for the generated image and for the photograph. The average ratio of section modulus (generated/photo) for all specimens was 0.994, which indicates that the proposed method is highly accurate. The section moduli of hollow trunks can be evaluated using the profile method together with the drill resistance technique on the condition that 26% of the trunk diameter could be drilled without skew.     

Accuracy and precision of crown profile,volume, and surface area measurements of 29-year-old Japanese cypress trees using a Spiegel relascope

The crown profile, volume, and surface area obtained from 25 trees in a stand of 29-year-old Japanese cypress (Chamaecyparis obtusa Endl.) using a Spiegel relascope were compared with those obtained by direct measurement after tree felling. In 17 of the 25 trees, the crown profile measured with the relascope was identical to the crown profile obtained by direct measurement. For the 17 trees, the mean relative errors of crown volume and surface area tended to be unbiased. On the other hand, the crown profiles obtained by the two methods were different in five of the 25 trees, while it could not been judged whether the crown profiles obtained by the two methods were identical or different in three of the 25 trees. However, for each group of five or three trees, the mean relative errors of crown volume and surface area were also unbiased. Moreover, for both crown volume and surface area, no significant differences were detected in variance of error among the groups of 17, five, and three trees. Therefore, the discrepancy between crown profiles obtained by the two methods for the five and three trees might be negligible in terms of the accuracy and precision of crown volume and surface area measurements. The standard errors for both crown volume and surface area were larger in each of the five and three trees than in the 17 trees. However, even for the five and three trees, the crown volume and surface area obtained using the relascope were more precise than those based on the assumption that crown form was a cone or paraboloid. We concluded that using a Spiegel relascope would enable us to obtain an accurate and precise crown profile, volume, and surface area of Japanese cypress trees for practical use, especially when the main objective of measurement is determining crown volume or surface area.     

沙柳重组木表面粗糙度的二维和三维分析对比

沙柳是我国东北地区广泛分布的一种速生沙生灌木,它具有耐寒、耐旱、砂埋藏高、适应性强、生长迅速等优良特性.高性能重组木是将沙柳在保留原有纤维排列的前提下,经过精细化疏解、浸胶、干燥、热压等工序加工成一种大截面、高强度、高耐候的均质结构材.作为一种建筑结构材料,其密度和尺寸可控,在一定程度上可以替代实木,大大提高了其附加值...     

焊接机器人三维防碰撞力传感器的设计

设计了一种三维防碰撞力传感器,其可利用一个输入实现x、y、z三个方向的碰撞力测试,用在6-D.O.F串联焊接机器人末端时,既可以实现对机器人本身的保护,也可以安装在其他设备的末端执行器上实现对设备的保护.     

Milling of wood and wood-based materials with a computerized numerically controlled router IV: development of automatic measurement system for cutting edge profile of throw-away type straight bit

In industrial machining of timber, the method in which the operator visually inspects both wear and chippings of router bits after stopping the machine is generally adopted. However, many working hours are lost in this method and productivity suffers. Therefore, the development of a system that can automatically measure wear or chippings without stopping the machine is desirable. In this study, a laser measuring instrument was installed in a computerized numerically controlled (CNC) router, and an automatic measurement system for the cutting edge profile of throw-away-type straight bits with single-edged blades was developed. The main results are summarized as follows: (1) an automatic measurement system for the cutting edge profile of the bit was constructed; (2) this system was composed of a laser measuring instrument, a control personal computer (PC) for the CNC router, and a monitoring PC to control some devices and collect sampling data; (3) the system could measure the cutting edge profile of the bit without stopping the CNC router.Part of this article was presented at the 51st and 52nd Annual Meetings of the Japan Wood Research Society, Tokyo and Gifu, April 2001 and 2002, respectively     

塑木地板的抗弯性能研究及断面分析

对目前常见的三种塑木地板进行抗弯性能研究,比较其抗弯弹性模量和抗弯强度,并根据材料力学理论对其断面结构的惯性矩、抗弯截面系数进行计算及断面分析。结果表明：对三种异型断面结构而言,空心型最为合理、实心型次之,开口型最差;将开口型地板下半部分的半圆直径从11mm减小到6mm,不仅节省材料,而且可以提高W／A,达到对抗弯性能的要求。     

Milling of wood and wood-based materials with a computerized numerically controlled router V: development of adaptive control grooving system corresponding to progression of tool wear

A laser measuring instrument was installed in a computerized numerically controlled (CNC) router, and an automatic measurement system, which was developed in a previous study, was used to automatically measure the cutting edge profile of throw-away type straight bits without stopping the CNC router. In addition to the above-mentioned system, in this study, an adaptive control program based on experimental data was installed, and an adaptive control grooving system that improved machining accuracy and controlled the burr formation corresponding to the progression of tool wear under processing was developed. Verification experiments of this system were carried out. The main results obtained are summarized as follows: (1) the between-process method was adopted for this system, and three types of processing methods (type 1, 2, 3), which consisted of a combination of an up-milling surface and a down-milling surface after processing, were investigated; (2) from the results of verification experiments, type 2 and type 3 methods showed remarkable ability to improve the machining accuracy and control the burr formation; and (3) it was found that the system employing adaptive control processing corresponding to the progression of tool wear in grooving is very effective. Part of this article was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002     

A comparison between three different methods of measuring knot parameters in picea abies

Both foresters and sawmillers are interested in the knot structure of trees; in particular, position and number of knots, knot diameter, knot length and dead knot border. For research purposes, it is possible today to carry out non‐destructive measurements using computer tomography (CT) and image analysis. The aim of this study was to measure knot parameters on Norway spruce (Picea abies (L.) Karst.) using a non‐destructive method developed for Scots pine (Pinus sylvestris L.), and to compare the results of this method with the results of two different destructive methods. In order to do this, two Norway spruce stems were scanned by CT. Then five logs from one stem were cut into flitches 20 mm thick and the defects on the sawn surfaces were scanned manually. The other stem was cut just above every whorl and then each knot was split through its centre and the knot parameters were measured manually. The study showed that the CT method compares well with the destructive methods. It is a reasonably fast, non‐destructive method which measures position and diameter of knots and detects larger knots with acceptable accuracy. The study also showed that a large number of smaller knots were not found by the CT method and that the CT method measured knot length and dead knot border with low accuracy. This means that the CT method has to be adjusted to Norway spruce in order to improve its ability to measure knot length and dead knot border and to detect smaller knots.     

桉树用材林林木资产评估的方法及应用

本文根据桉树速生、短轮伐期的特点,结合用材林林木资产评估方法,按立地等级差异进行桉树林地的资产评估。充分考虑桉树调查小班的林龄及生长状况,按照经营成本、利息、利润及税收等因素对林木资源价值量及其分布结构进行核算评估。通过应用案例分析,用常规的评估方法对速生桉用材林进行评估不能合理地反映林木资产价值。针对幼龄林采用重置成本法评估其林木价值,在栽植时至评估基准日期间,林木因快速生长所产生的价值不能体现。而采用“现行市价法”进行评估,是对有蓄积的幼龄林林木资产价值评估的首选方法,可真实反映其林木价值,为桉树林地林权流转提供可靠的依据,在生产实践中切实可行。     

没食子酸辛酯标准样品的研制

研究了没食子酸辛酯标准样品的制备、均匀性和稳定性及其定值试验。将没食子酸辛酯工业品用无水乙醇溶解,再用纯水稀释后重结晶,得到高纯度的没食子酸辛酯标准样品。没食子酸辛酯含量测定采用液相色谱面积归一化法。所研制的没食子酸辛酯标准样品通过了均匀性检验和稳定性检验(6个月)。经定值检测,该标准样品的质量分数为99.472 0%,不确定度为0.03%。     

Microscopic observation of transverse swelling of latewood tracheid: effect of macroscopic/mesoscopic structure

In order to study the transverse swelling/shrinkage of wood, the microscopic swelling behavior of latewood tracheid was observed using confocal laser scanning microscopy and the digital image correlation method. A microcrater structure was created on the surface of the specimen by using the ion sputter etching technique to obtain a pattern-rich digital image for image analysis. Douglas fir specimens were conditioned by two methods of absorption: rapid absorption of moisture from hot steam, and slow absorption of moisture from the water vapor of saturated solutions. Latewood tracheid near the surface of the specimen deformed only in the radial direction when the relative humidity of the surrounding air changed rapidly (rapid absorption of moisture from hot steam or absorption/desorption of moisture during the observation). In addition, the diameter of the lumen decreased upon rapid absorption of moisture, whereas it expanded upon slow absorption of moisture. These results indicate that the microscopic swelling behavior of latewood cells is strongly influenced by the macroscopic/mesoscopic structure, for instance, the cell arrangement or the alternation of latewood and earlywood. Part of this report was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

广西集中连片特殊困难地区林业发展探讨

广西集中连片特殊困难地区位于广西的北部、西北部和西南的大部,是滇桂黔石漠化综合防治核心区之一,片区涉及7个市35个县,贫困人口504.4万,集革命老区、边境地区、少数民族聚居区、大石山区、库区于一体,林地面积740.97万km2,也是矿区、水能、旅游、农林产品、民族文化等资源富集区。根据片区的现状和资源,分析存在的问题和发展潜力,建议特殊地区按功能区划、按特色林业经济带和特色产业组团的布局方法来发展林业经济。     

Stem water transport of Lithocarpus edulis, an evergreen oak with radial-porous wood

The stem water conducting system of an evergreen broad-leaved oak, Lithocarpus edulis (Mak.) Nakai, was investigated. Evergreen broad-leaved oaks (Lithocarpus, Castanopsis, Cyclobalanopsis, Quercus) belonging to the Quercoideae are a major component of Asian monsoon forests, and are characterized by the possession of radial-porous wood. A characteristic of radial-porous wood is the development of aggregate rays between radially oriented files of vessels. We measured the distribution of vessel lumen diameters in a stem cross section and calculated the theoretical water conductivity of the wood. The radial profile of the heat pulse velocity (HPV) was measured for an intact whole tree under field conditions and compared with the theoretical distribution of water conductivity. Soft X-ray photographs of frozen stem sections indicated that most of the vessel lumina were filled with water, including those of vessels more than 20 years old. Even when vessels were relatively wide (lumen diameters > 100 microm), cavitation was negligible. The rate of water uptake from the cut stem base correlated closely with HPV (r = 0.96), and HPV closely reflected the mean volume flow per stem sectional area (SFVS) around the sensor probes. However, the ray tissue sharply inhibited heat transfer, and the positioning of the probes strongly affected the absolute value of HPV. It was also found that HPV more closely reflected the mean sap flow velocity in the vessels than did SFVS.     

Forest shadows: How much shelter in a shelterwood?

A simulation model is presented that will permit silviculturists to estimate the shade cast on any site at any time by a randomly distributed conifer stand of any stocking level. Computational requirements are modest. Simple situations may be solved in an hour or so on a programmable hand calculator; most complex situations can be handled on a desk microcomputer.Trees are modelled as a crown consisting of a cone on top of a cylinder, and the crowns may vary in density. The bole is modelled as a solid cylinder. Relative dimensions may be varied to simulate almost all regular conifer tree forms. The projected shadow area of trees is integrated for any number od independently distributed trees to obtain the relative shadow area on the ground surface. Alternatively, the model permits the determination of the number of trees of any given dimensions per unit are needed to provide a given degree of shade.     

A rapid technique for recording and measuring the leaf area of conifer needle samples

An optical planimetric technique for measuring projected leaf area of conifer needle samples was developed that combines a rapid field recording method with an inexpensive hand-held optical scanner. The field recording method utilizes strips of diazo paper (blueprint paper), 10 x 28 cm, to make positive images of the needle samples. An analysis program calculates leaf area from the output files produced by the hand-held scanner. The results from this system were compared with results from a Li-Cor 3100 leaf area meter and from a digital camera-based image analysis system using both standard samples of known area and needle samples from three conifer species. All three systems produced similar results in terms of means and variances. The digital camera system typically had the lowest variances between successive measurements of the same sample. Most differences among the systems were not statistically significant. The system presented in this paper is inexpensive, easy to use, and provides a rapid and permanent method for recording and measuring the leaf area of conifer samples.