【作者】 侯卫萍；

【导师】 王立海；

【作者基本信息】 东北林业大学 ， 森林工程， 2011， 博士

【摘要】 木材是一种人类使用历史最长的可再生的天然资源。随着社会进步,人们对生产生活质量要求的提高,对木材的需求量逐渐增加。充分有效地利用木材资源,使之产生最大的经济与社会效益,是各国林业科研工作者共同关心和不断研究的课题。应力波无损检测技术作为木材无损检测技术中的一种在过去几十年得到了迅速的发展,国内外研究表明,应力波技术在木材的内部缺陷检测、在线产品的质量控制、树木的保护等方面有广阔的应用前景。本文利用VC++和OpenGL平台实现了原木内部腐朽的三维重构,可以准确地判别出原木内部腐朽立体形状及尺寸,从而为原木缺陷检测、原木合理分级、合理造材与造材加工自动化生产、立木健康评价、木制建筑的强度评价提供应用理论基础和科学依据。研究结果对减少木材的损失和浪费,提高我国原木利用率具有重要的意义。三维重建技术是20世纪80年代后期迅速发展起来的一门新兴技术,是科学计算可视化的一个重要研究领域,而科学计算可视化是当前计算机学科的一个重要研究方向。由断层数据重构物体的三维模型是一种常用的数据场可视化技术。其研究目标是把试验或者数值计算获得的大量数据转化为人的视觉可以感受的计算机图像。本文首先分析了应力波在原木横截面传播理论、传播规律和应力波木材无损检测系统的工作原理并以此设计实验得到应力波无损检测仪的最佳工作条件,在此基础上,利用ARBOTOM应力波木材无损检测系统获取得到一组原木内部腐朽断层图；其次,应用数字图像处理技术对获取到的断层图像进行预处理,预处理的目的主要是消除图像在采集、储存、传递、提取过程中产生的噪声和伪像,包括滤波降噪处理和图像增强处理,以使原木内部腐朽更加清晰,便于人眼识别和为后续处理作准备,在这里,根据本文的实际需要对现有的图像处理方法进行对比研究,选择出最适合的图像预处理方案；然后,对进行预处理后的断层图像进行图像分割,并利用数学形态学方法对阈值分割后的图像进行处理,消除无用信息,保留有用的信息；利用边缘检测算子提取出原木边界轮廓以及反映原木内部腐朽信息的边缘；在轮廓线的连续性处理中引入B样条曲线来拟和轮廓线以改善其连续性；然后进行了轮廓线拼接计算工作,并且以三角形形状最优为目标提出了基于Delaunay三角剖分的轮廓线的拼接算法。最后对断层图像进行层间插值并在OpenGL平台下完成原木内部腐朽的三维重构,确定原木内部腐朽三维结构形状,实现原木内腐缺陷检测,从而为原木缺陷检测、原木合理分级、合理造材与造材加工自动化生产、立木健康评价、木制建筑的强度评价提供应用理论基础和科学依据。更多还原

【Abstract】 Wood is a human use history’s longest renewable natural resources. With the social progress, people to production, life quality requirements enhancement, to lumber demand to increase gradually. Fully effectively use timber resources, to produce the maximum economic and social benefits of forestry science research workers, is the world care together and continuously research topic. Stress wave nondestructive testing technology as the wood nondestructive testing technology in the past decades obtained a rapid development and the domestic and foreign research shows that stress wave technology in wood of internal defects detection, the online product quality control, trees on protection of have broad application prospects. This paper using vc++and OpenGL platform realized three-dimensional reconstruction internal decaying log, can accurately discriminant out internal decaying log, and three-dimensional shape and size for log defects detection, log reasonable classification, reasonable made material and build material processing LiMu automation production, health evaluation, wooden building strength assessment theoretical basis and provide scientific basis for the application. The results of the study of wood reduction loss and waste, enhances our country log utilization has the vital significance.3D reconstruction technique is the late1980s rapidly develop a new technology, is scientific computing visualization one of important research fields, and scientific computing visualization is the current computer science, one of the important research direction. The fault data reconstruction objects by3D model is a common data field visualization technology. The study aims to test or numerical calculation of large quantities of data transformation of human visual can feel computer images.This paper first analyzes the stress wave in the logs cross-sectional media theory and spread rule and stress wave wood working principle of nondestructive testing (NDT) system, and based on this ARBOTOM stress wave wood, use nondestructive system obtain get a group of log internal decayed fault figure; Secondly, the application of digital image processing technique, the fault image obtained the main purpose of pretreatment and pretreatment is to eliminate image in acquisition, storage, transfer, extraction process of the noise and pseudo like, including filtering noise reduction processing and image enhancement processing, to make more clear, decaying log internal eye identification for follow-up for preparing and handling, according to the actual need of existing paper image processing method of comparative study, choose the most suitable image preprocessing scheme; Then, after pretreatment of fault for image segmentation image, and by using the method of mathematical morphology after threshold segmentation image processing technology, eliminate useless information, retain useful information; Using edge detection operators extract log boundary contours and reflect the edge of internal decaying log information; The continuity of the Outlines in processing b-spline curve introduced to fit and contour line to improve its continuity; Then, contour line joining together with computational tasks, and the optimal triangular shapes for target was proposed based on Delaunay triangulations profile stitching algorithm. Final between layers of fault image interpolation and finish the workbench in OpenGL3D reconstruction internal decaying log, internal decaying log internal decayed3D structure to determine the shape, realization log corrosion defects detection within, thus for log defects detection, log reasonable classification, reasonable made material and build material processing automation production, trees health evaluation, wooden building strength assessment theoretical basis and provide scientific basis for the application.更多还原