基于三维激光扫描技术的大型古建筑精细三维重建

大型古建筑文物结构复杂,数字化保护工作繁琐且沉重,而三维激光扫描技术作为测绘领域的一项高新技术,具有无接触测量、效率高等优点,将三维激光扫描技术应用到文物保护领域将成为精细、快捷的文物档案保护手段之一。以某大型仿古建筑为例,详细阐述了数据采集的技术和方法,结合在数据处理过程遇到的一些问题进行了探讨和总结。最终给出该建筑物的局部纹理映射图和各类效果图,为三维激光扫描技术在大型古建筑三维重建中的应用提供借鉴和参考。     

基于三维激光扫描的汽车零部件逆向设计研究

采用三维激光扫描技术,结合逆向软件Geomagic Studio和三维设计软件CATIA对汽车座椅进行逆向设计.首先介绍了汽车座椅的三维扫描、数据采集和点云处理过程,然后进行曲面设计和数字化建模,获取汽车座椅的三维和二维图形,最后探讨了两种3D打印模式在汽车座椅快速成型上的应用,证实了三维扫描和3D打印在汽车座椅逆向设计及制造中的可行性.     

3D cavity detection technique and its application based on cavity auto scanning laser system

Ground constructions and mines are severely threatened by ones. Safe and precise cavity detection is vital for reasonable cavity underground cavities especially those unsafe or inaccessible evaluation and disposal. The conventional cavity detection methods and their limitation were analyzed. Those methods cannot form 3D model of underground cavity which is used for instructing the cavity disposal; and their precisions in detection are always greatly affected by the geological circumstance. The importance of 3D cavity detection in metal mine for safe exploitation was pointed out; and the 3D cavity laser detection method and its principle were introduced. A cavity auto scanning laser system was recommended to actualize the cavity 3D detection after comparing with the other laser detection systems. Four boreholes were chosen to verify the validity of the cavity auto scanning laser system. The results show that the cavity auto scanning laser system is very suitable for underground 3D cavity detection, especially for those inaccessible ones.     

Monitoring slope deformation using a 3-D laser image scanning system:a case study

An ILRIS-36D 3-D laser image scanning system was used to monitor the Anjialing strip mine slope on Pingshuo in Shanxi province.The basic working principles,performance indexes,features and data collection and processing methods are illustrated.The point cloud results are analyzed in detail.The rescale range analysis method was used to analyze the deformation characteristics of the slope.The results show that the trend of slope displacement is stable and that the degree of landslide danger is low.This work indicates that 3-D laser image scanning can supply multi-parameter,high precision real time data over long distances.These data can be used to study the distortion of the slope quickly and accurately.     

快速三维扫描激光雷达的设计及其系统标定

为了增强传统二维激光雷达的环境几何信息采集能力,设计了一个快速三维扫描激光雷达系统.采用了一个单片机控制的步进电机旋转二维激光雷达的扫描平面,得到第三维扫描.研制了高速数据通讯卡,实现激光雷达与数据采集计算机之间的实时传输.在整个扫描过程中,各个时刻的二维距离测量数据和相应的俯仰扫描角被同时记录下来,形成一帧完整的三维距离图像.在分析系统误差源基础上,对初始姿态误差和系统偏心误差建立了数学模型,并采用最小二乘法作了系统标定.实验结果表明,该雷达系统精度高,在量程范围内距离误差小于±30 mm,扫描速度可达1.2 s/帧数据.     

基于三维激光扫描的高陡边坡块体稳定性研究

艰险山区工程建设中高陡边坡块体稳定性是安全与防灾的重要问题,对艰险山区高陡边坡岩体结构面的调查是分析该问题的关键。以澜沧江某重大工程高边坡为研究对象,应用三维激光扫描技术,研究了远距离调查分析岩体结构的分析方法,分析了该高陡边坡的岩体结构面空间分布状况,统计分析了结构面的优势方向和岩石块体的分布状况,以此为基础,应用极限平衡分析方法,研究了该高陡边坡的岩石块体稳定性。     

基于点云数据的预制叠合板尺寸质量智能检测方法

为保证预制叠合板在施工现场能顺利安装,在出厂前通常需要对其进行尺寸质量检测,现有预制叠合板的尺寸质量检测方法难以全面准确地测量叠合板的实际三维尺寸。提出一种基于预制叠合板点云数据的多尺寸质量智能检测方法。对采集的点云数据进行预处理后,利用机器学习算法完成预制叠合板点云的自动定位与分割;依据不同的检测任务,将目标点云沿不同方向降维,映射为二维灰度图像;利用图像特征检测算法,分别实现叠合板底板的长宽、预留胡子筋的出筋长度与间距及桁架钢筋高度的自动检测;在验证试验中,对3块预制叠合板的点云数据进行尺寸质量检测。结果表明,提出的智能检测方法能全面准确地完成预制叠合板出厂尺寸质量检测,能进一步提高预制叠合板非接触质量检测结果的科学性与精准性。     

三维时间基线视差法在变形监测中的应用研究

利用数码相机进行钢结构的变形监测是对传统近景摄影方法的变革,但数码相机属于非测量相机,它没有框标及定向设备,摄影瞬间的内、外方位元素的初始值是无法得到的。因此,常规解法无法解决数码相机获取测量数据的计算处理问题,对此时间基线视差法有其特殊优势。利用三维时间基线视差法处理钢结构变形测量数据的解算方法,给出了实验结果。该方法考虑了分辨率、焦距以及外界环境条件的影响,采用有效的方法进行消除,取得了观测误差小于2/1000的结果。     

基于移动激光扫描系统Trimble MX8的杆状地物提取研究

介绍车载移动三维激光扫描测量系统的发展和特点,以及Trimble MX8系统的构成和功能应用,重点阐述当前国内学者从激光点云数据中提取杆状地物的方法.通过选择两条不同的道路,在不同道路环境下应用不同的参数对杆状地物进行提取,显示不同的提取结果.通过对实验结果进行对比分析得出：面对不同的道路环境,采用相适宜的参数,再加以人工细致的检查,从激光点云数据中提取杆状地物的结果还是可以满足需要的.     

三维激光扫描测量采样要素关系研究

在工程测量中,进行三维激光扫描时,扫描测量数据的质量与扫描采样间隔、激光光斑大小、扫描距离有关。研究发现,激光光斑大小与扫描距离呈线性变化关系,且激光光斑具有边缘效应,扫描距离和最小采样间隔的关系也呈线性变化关系。     

3D TLS在相似模型开采实验中的应用研究

提出了将地面三维激光扫描应用于相似材料模型实验的扫描观测。基于扫描得到的点云图像进行三维数字建模,通过特征提取获取每一期次模型上标志点三维坐标,绘制了地表下沉随工作面推进的动态沉陷过程曲线。此外,用该方法建立的三维模型还可以在日后再现当时的顶板断裂垮落过程,克服了传统观测方法随着模型的损毁而无法再次获取模型表面数据的局限性,为地表实测数据与模型观测值的对比研究提供了新的途径。     

摄像机与3D激光雷达联合标定的新方法

针对摄像机与3D激光雷达融合系统的标定问题,提出了一种基于平面标定模版的新方法.整个标定过程分为单传感器独立标定和多传感器联合标定两部分.与以往的基于特征点或者边缘对应的标定方法不同,根据传感器原点到标定平面的距离对应性原理实现了联合标定,解决了在激光雷达距离图像上提取特征点或者边缘时精度较低带来的问题.同时,仅采用同一块平面模板完成了整个标定过程,简单实用.实验结果表明,相比传统标定方法,本方法能够获得更高的精度.     

Kriging点云滤波改进算法及监测试验研究

为进一步提高三维激光扫描技术的量测精度,从优化滤波算法的角度出发,基于Kriging改进算法,考虑描述对象的空间相关性质,针对点云数据的滤波处理问题,研究点云格网化滤波的优化方法。以实际工程为依托,通过现场监测比对试验,对三维激光点云数据进行格网化处理和分析,将试验得出的变形数据与传统方法的量测数据进行对比。结果表明：基于Kriging滤波的改进算法不仅能够高效识别和提取隧道轮廓断面可视化数据,而且可以高效、准确地获得隧道变形;试验的拱顶下沉数据与传统量测数据较接近,而周边收敛数据则有一定的差异。三维激光扫描技术下的隧道变形监测在一定的环境条件下能较好地反映隧道变形的真实情况,为隧道工程的施工提供有效的安全预警。     

三维虚拟变电站数字可视化管理与监控系统

研究面向变电站营运管理的三维虚拟数字可视化系统,将三维虚拟和数字可视化技术与变电站现有系统与信息集成起来,包括PMIS系统、实时监控系统、实时视频监控系统、火灾报警系统、安全防护系统等,实现变电站各种信息的一体化多维展示,解决目前变电站各种系统以二维方式离散展示信息的缺陷,提高变电站的运行管理与监控水平.     

Cavity 3D modeling and correlative techniques based on cavity monitoring

According to the mining method for Dongguashan Copper Mine and Tongkeng Mine in China, and with the help of the cavity monitoring system（CMS） and mining software Surpac, the 3D cavity models were established exactly. A series of correlative techniques for calculating stope over-excavation and under-excavation, stope dilution and ore loss rates, and the blasting design of the pillar with complicated irregular boundaries were developed. These techniques were applied in Dongguashan Copper Mine and Tongkeng Mine successfully. Using these techniques, the dilution rates of stopes 52-2^#, 52-6^#, 52-8^#and 52-10^# of Dongguashan Copper Mine are calculated to be 2.12%, 8.46%, 12-67% and 10.68%, respectively, and the ore loss rates of stopes 52-6^# and 5-8^# are 4.41% and 3.70%, severally. Furthermore, according to the design accomplished by the technique for a pillar of Tongkeng Mine with irregular boundary, the volume, total length of boreholes and the dynamite quantity of the pillar are computed to be 1.2 ×10^4 m^3, 2.98 km and 10.97 t, correspondingly.     

激光测距成像雷达三维测距：存在问题及解决方法

激光测距成像雷达获取三维距离图具有许多众所周知的优点，然而也存在某些弊端。本文的目的就是研究这些弊端。重点是提出了克服每一弊端的针对性策略。     

交互式三维场景生成技术的研究与实现

介绍了如何将OpenGL提供的底层功能与面向对象的程序设计思想相结合进行交互式三维图形系统的设计过程,研究了以下几方面内容,（1）三维参数化建模的实现;（2）三维过程的连续显示的问题;（3）三维图形交互功能的实现,并取得了满意的效果。     

A robust approach to identify roof bolts in 3D point cloud data captured from a mobile laser scanner

Roof bolts such as rock bolts and cable bolts provide structural support in underground mines. Frequent assessment of these support structures is critical to maintain roof stability and minimise safety risks in underground environments. This study proposes a robust workflow to classify roof bolts in 3 D point cloud data and to generate maps of roof bolt density and spacing. The workflow was evaluated for identifying roof bolts in an underground coal mine with suboptimal lighting and global navigation satellite system(GNSS) signals not available. The approach is based on supervised classification using the multi-scale Canupo classifier coupled with a random sample consensus(RANSAC) shape detection algorithm to provide robust roof bolt identification. The issue of sparseness in point cloud data has been addressed through upsampling by using a moving least squares method. The accuracy of roof bolt identification was measured by correct identification of roof bolts(true positives), unidentified roof bolts(false negatives), and falsely identified roof bolts(false positives) using correctness, completeness, and quality metrics. The proposed workflow achieved correct identification of 89.27% of the roof bolts present in the test area. However, considering the false positives and false negatives, the overall quality metric was reduced to 78.54%.     

Growth Mechanism and Characterization of ZnO 3D Nanocrystals by Laser Irradiation ＆ Coaxially Transporting O2

Different three-dimension （3D） nanotetrapods, containing club-like nanocrystals, nanotetrapods and four-foot-like nanocrystals were synthesized from Zinc sheet via CO2 laser irradiation and coaxially transporting O2. Different nanoproducts were fabricated by changing the content of oxygen in the experiment. The morphologies, components, phase structures and optical properties of the products were investigated by a field-emission scanning electron microscopy, an X-ray diffraction, an energy dispersed X-ray spectrometer and a photoluminescence spectroscope. The X-ray diffraction spectra were obtained on a Rigaku D/max 2500PC diffractometer. The experimental results reveal that high quality ZnO nanotetrapods can be fabricated on the special parameters, and growth of ZnO nanotetrapods depends on Vapour-Liquid-Solid（VLS） model, and the content of oxygen in the gas, namely, oxygen partial pressure is one of main factors to control morphologies and optical properties ofZnO nanotetrapods; these advantages above are important for realization of optoelectronic devices.     

Growth Mechanism and Characterization of ZnO 3D Nanocrystals by Laser Irradiation & Coaxially Transporting O2

Different three-dimension (3D) nanotetrapods,containing club-like nanocrystals,nanotetrapods and four-foot-like nanocrystals were synthesized from Zinc sheet via CO2 laser irradiation and coaxially transporting O2.Different nanoproducts were fabricated by changing the content of oxygen in the experiment.The morphologies,components,phase structures and optical properties of the products were investigated by a field-emission scanning electron microscopy,an X-ray diffraction,an energy dispersed X-ray spectrometer and a photoluminescence spectroscope.The X-ray diffraction spectra were obtained on a Rigaku D/max 2500PC diffractometer.The experimental results reveal that high quality ZnO nanotetrapods can be fabricated on the special parameters,and growth of ZnO nanotetrapods depends on Vapour-Liquid-Solid(VLS) model,and the content of oxygen in the gas,namely,oxygen partial pressure is one of main factors to control morphologies and optical properties of ZnO nanotetrapods;these advantages above are important for realization of optoelectronic devices.