Research on wind erosion processes and controlling factors based on wind tunnel test and 3D laser scanning technology

The study of wind erosion processes is of great importance to the prevention and control of soil wind erosion.In this study,three structurally intact soil samples were collected from the steppe of Inner Mongolia Autonomous Region,China and placed in a wind tunnel where they were subjected to six different wind speeds(10,15,17,20,25,and 30 m/s)to simulate wind erosion in the wind tunnel.After each test,the soil surfaces were scanned by a 3D laser scanner to create a high-resolution Digital Elevation Model(DEM),and the changes in wind erosion mass and microtopography were quantified.Based on this,we performed further analysis of wind erosion-controlling factors.The study results showed that the average measurement error between the 3D laser scanning method and weighing method was 6.23%for the three undisturbed soil samples.With increasing wind speed,the microtopography on the undisturbed soil surface first became smooth,and then fine stripes and pits gradually developed.In the initial stage of wind erosion processes,the ability of the soil to resist wind erosion was mainly affected by the soil hardness.In the late stage of wind erosion processes,the degree of soil erosion was mainly affected by soil organic matter and CaCO_(3)content.The results of this study are expected to provide a theoretical basis for soil wind erosion control and promote the application of 3D laser scanners in wind erosion monitoring.

Research on 3D Laser Scanning Reconstruction of Ancient Buildings Combined with BIM Technology

After more than 30 years of scientific and social development, surveying and mapping technology by leaps and bounds, engineering surveying technology has undergone tremendous changes. In the process of protecting ancient buildings, it is necessary to obtain the precise dimensions of architectural details. In this study, the path of 3D laser scanning combined with BIM technology is explored. Taking the observation and protection of the ancestral hall of the Liu family as an example, this study aims to draw drawings that reflect the relevant information about the ancient buildings, the accurate three-dimensional model of ancient buildings is established with BIM technology, which provides new methods and ideas for the research and protection of ancient buildings. .

The Research Application of 3D Laser Scanning Technology in the Deformation Detection of Large Cylindrical Oil Tank

In order to ensure the safety in using a large cylindrical storage tank,it is necessary to regularly detect its defonnatioii.The traditional total station method has high accuracy in determining the deformation,however,it has a low measxirement efficiency.Long-term observation means,there are more risks in the petrochemical plant,therefore,this paper proposes the usage of the 3D laser scanner,replacing the traditional total station to determine the defbnnation of a large cylindrical storage tank.The Matlab program,is compiled to calculate the point cloud data,while the tank deformation is analyzed from two different points which are,the local concave convex degree and the ovality degree.It is concluded that,the difference between the data obtained by 3D laser scanning,and total station is within the range of oil tank deformation limit,therefore,3D laser scanner can be used for oil tank deformation detection.

Algorithm and System of Scanning Color 3D Objects

This paper presents a complete system for scanning the geometry and texture of a large 3D object, then the automatic registration is performed to obtain a whole realistic 3D model. This system is composed of one line strip laser and one color CCD camera. The scanned object is pictured twice by a color CCD camera. First, the texture of the scanned object is taken by a color CCD camera. Then the 3D information of the scanned object is obtained from laser plane equations. This paper presents a practical way to implement the three dimensional measuring method and the automatic registration of a large 3D object and a pretty good result is obtained after experiment verification.

基于线阵CCD的折射率和浓度测量装置

本文提出了一种结合激光器和线阵CCD的折射率测量方法,利用光线穿过平行板介质时产生横向位移的特性,实现对透明介质折射率和浓度的高效、准确测量。装置采用红色点状激光器作为稳定光源,并通过衰减片削弱光强,利用旋转平台精确调整入射角,最后用线阵CCD传感器捕捉光斑位置变化,再录入Matlab程序中,实现对介质折射率以及透明液体浓度的实时测量。

A Study of Precision Factors of Large-scale Object Surface Profile Laser Scanning Measurement

In this paper, we presented a method of using the l as er scanning triangulation for the non-contact 3D surface profile measurement of large-scale object. The characteristic of large-scale object non-contact mea surement is analyzed and the measuring method is proposed. Main factors influenc ing measurement precision such as image distortion and accurate designation of s peckle center are analyzed and methods of solving these problems are proposed. W e designed a combined filter by which the pulse noise and the Gaussian noise of speckle image can be eliminated efficiently. Using the characteristic of intensi ty distribution of laser speckle image we proposed a new approximating method th at could locate the center of laser speckle image at sub-pixel. The auxiliary v ariables are set to linearize the relationship between the image displacement an d the distance, the accurate values of laser triangulation system parameters cou ld be calibrated accurately and the measuring precision is increased remarkabl y. Using the above techniques we designed a measuring system based on laser sc anning triangulation. The results of the experiment show that these methods can raise the measuring precision of large-scale 3D surface profile effectively.

High Speed Laser 3D Measurement System

Using the method of line structure light produced by a laser diode,three dimensional profile measurement is deeply researched.A hardware circuit developed is used to get the center position of light section for the improvement of the measurement speed.A double CCD compensation technology is used to improve the measurement precision. An easy and effective calibration method of the least squares to fit the parameter of system structure is used to get the relative coordinate relationship of objects and images of light section in the directions of height and axis. Sensor scanning segment by segment and layer by layer makes the measurement range expand greatly.

基于CCD的电子散斑干涉系统中离面位移的测定

简要介绍电子散斑干涉系统的组成部分、散斑干涉原理以及离面位移测量的检测原理,并采用了最新处理光学信息的CCD测量技术,利用软件画出测试表面受力变形后的三维重构图,同时得出变形后物体在X方向和Y方向的离面位移.

基于CCD技术的钢板测宽仪

在原有的钢板在线测宽仪的基础上,提出了一种采用经济的线阵CCD成像的改良型系统。介绍了测量方法以及原理,应用CPLD与单片机结合采集与处理测量数据,采用边缘细化技术提高测量精度。整套系统结构简洁,成本低廉,抗干扰性能好,调试方便。

线阵CCD技术在钢板测宽仪中的应用

国内目前钢板测宽仪,其结构复杂,控制繁琐,需要标定,以及及时维护,实时操作性差。本文在原有的钢板在线测宽仪的基础上,提出了一种改良型的系统。系统中采用经济的线阵CCD成像系统。在本文中介绍了测量方法,以及原理,应用CPLD与单片机结合采集与处理测量数据,和边缘细化技术提高测量精度。整套系统结构简洁,成本低廉,抗干扰性能好,调试方便。

基于线阵CCD的二维轮廓扫描系统

吊装过程中为获取吊物具体位置信息,设计了一种基于线阵CCD的二维轮廓扫描系统。利用激光照射直线与线阵CCD投影直线相交的原理求取激光照射点二维坐标;提出了一种基于硬件的线阵CCD脉冲中心位置测量方法;采用双直线法对线阵CCD进行标定,得到其输出像素坐标与投影直线的映射关系;研究提出了一种升降速控制策略,能平稳高效地控制步进电机。用已知尺寸的圆柱形PVC管作为实验对象,系统测得其二维轮廓若干离散点坐标,通过圆周拟合的方式得到圆柱半径,平均误差为0.928 mm,系统一次扫描耗时约0.45 s;实验结果表明,系统测量精度较高,扫描速度较快,可广泛应用于物体的二维轮廓扫描。

Indoor Space Modeling and Parametric Component Construction Based on 3D Laser Point Cloud Data

In order to enhance modeling efficiency and accuracy,we utilized 3D laser point cloud data for indoor space modeling.Point cloud data was obtained with a 3D laser scanner and optimized with Autodesk Recap and Revit software to extract geometric information about the indoor environment.Furthermore,we proposed a method for constructing indoor elements based on parametric components.The research outcomes of this paper will offer new methods and tools for indoor space modeling and design.The approach of indoor space modeling based on 3D laser point cloud data and parametric component construction can enhance modeling efficiency and accuracy,providing architects,interior designers,and decorators with a better working platform and design reference.

基于结构光技术的3D激光扫描测量系统

提出了一种基于结构光技术的3D激光扫描测量系统。介绍了该测量方法的基本原理、系统结构及对拍摄数据的提取、转换、运算方法。通过实验对两种不同材料在高度和宽度方向进行实际测量,并将测量结果进行了分析比较。结果表明对不同材料的测量精度不同,反射率高的材料测量精度更高,且平均误差率均在1%以内,符合实际需求。

不同分辨率DEM提取切沟形态特征参数的转化研究

选取黄土丘陵区岔巴沟流域不同位置和不同沟道级别的30条典型切沟为研究对象,基于三维激光扫描技术(LIDAR),建立了基于高分辨率DEM提取切沟形态特征的方法,对比分析了0.1m与5m2种分辨率DEM提取切沟形态特征参数的差异,实现对低分辨率DEM提取的切沟形态特征参数向高分辨率尺度转化。结果表明:基于三维激光扫描技术获取的0.1m高分辨率DEM提取的切沟形态特征值与手工测量的切沟形态特征值之间无显著差异,三维激光扫描技术提取的切沟长度、宽度、深度、表面积和体积分别是手工测量的94.0%,109.1%,107.7%,80.1%和109.0%,表明三维激光扫描技术获取的0.1m高分辨率DEM可较准确地描述切沟形态特征。0.1,5m2种分辨率DEM提取的切沟长度间无显著差异,但2种分辨率DEM提取切沟宽度、深度、表面积和体积间差异显著。5m分辨率DEM提取的切沟宽度、表面积和体积分别较实际值分别偏大28.6%,25.6%和19.7%;而其提取的切沟深度较实际值偏小37.0%。据此,通过模型筛选,分别建立了0.1m高分辨率DEM与5m分辨率DEM提取的切沟宽度、表面积和体积转换模型。模型验证结果表明,本研究所构建的切沟宽度、表面积和体积转换模型的决定系数均大于0.6,模型有效性系数均大于0.5,说明3个转换模型均具有较好的预报精度,为研究黄土丘陵区沟蚀特征提供了重要方法和手段。

3D激光扫描技术在地铁隧道断面收敛测量中的应用

地铁隧道断面收敛测量是地铁施工和日常监护的重要内容,关系到隧道整体的稳定性和安全性。3D激光扫描技术利用其高采样率,能提供全面、高精度的数据,为地铁施工及运营提供安全预判的直观、精确数据,具有传统测量方法难以完成的技术优势。本文对比传统方法与3D激光扫描技术的特点,给出3D激光扫描技术在地铁隧道断面收敛测量中的应用方法,并结合具体案例,深入分析3D扫描技术测量的内符合性和外符合性。

基于3DSLAM移动扫描技术的地下空间测量方法研究

针对传统的城市地下空间测量方法存在的困难和问题,试验了一种基于3DSLAM(Simultaneous Localization And Mapping—实时定位与制图)移动扫描技术的地下空间测量新方法。采用i MS3D三维移动测量扫描仪对南京市新街口地区的地下空间进行了扫描测量,分别对地下停车场、地下通道、地下商场等不同类型的地下空间进行了快速高效的三维激光点云数据采集和实景影像采集,通过后处理软件,实现了对不同地下空间结构的测量,测量结果满足相关规范要求,同时还实现了对地下空间主要建(构)筑物的三维建模及实景影像管理。试验结果表明:该技术不仅可以快速有效地对地下空间进行快速有效的数据采集和测量,还可以同步构建三维模型及实景影像,为城市地下空间测量提供了一种新的技术手段。

Methods of configuration test and deformation analysis for large airship

In recent years, high-altitude aerostats have been increasingly developed in the direction of multi-functionality and large size. Due to the large size and the high flexibility, new challenges for large aerostats have appeared in the configuration test and the deformation analysis. The methods of the configuration test and the deformation analysis for large airship have been researched and discussed. A tested method of the configuration,named internal scanning, is established to quickly obtain the spatial information of all surfaces for the large airship by the three-dimensional(3D) laser scanning technology. By using the surface wrap method, the configuration parameters of the large airship are calculated. According to the test data of the configuration, the structural dimensions such as the distances between the characteristic sections are measured. The method of the deformation analysis for the airship contains the algorithm of nonuniform rational B-splines(NURBS) and the finite element(FE)method. The algorithm of NURBS is used to obtain the reconfiguration model of the large airship. The seams are considered and the seam areas are divided. The FE model of the middle part of the large airship is established. The distributions of the stress and the strain for the large airship are obtained by the FE method. The position of the larger deformation for the airship is found.

基于3D激光扫描技术在建筑立面测量中的应用

3D激光扫描是运用非接触式高速激光测量,从而获得目标对象的三维坐标和数码影像的方法。能够更加高效的获得大型实体或实景等目标的三维立体信息。文章结合某建筑立面测量实例,借助3D激光扫描技术的优势,提出基于该技术的作业流程,通过应用实践的检验,并取得了较好的成效,积累了实践经验。

基于3D激光扫描的金属矿测量方法研究

随着数字化技术的不断发展,三维激光扫描技术在金属矿产勘查中的应用越来越广泛;由于其实时动态、数字化、非接触测量等优点,已成为目前我国金属矿山勘探与开发领域的技术中心,特别是在隧道测量中,利用这种技术可以更快、更直观地获得地下隧道与地表间的空间信息。本文就三维激光扫描仪的含义、特点及原理作一简要介绍,并就如何在实际的金属矿测量中改进这种技术的效果作一探讨。

ACQUIREMENT AND COMPUTER PROCESSING OF 3-D SURFACE SHAPE DATA

The laser scanning and CCD image-transmitting measurement method and principle on acquiring 3-D curved surface shape data are discussed. Computer processing technique of 3-D curved surface shape(be called“ 3 - D surface shape”for short) data is analysed. This technique in- cludes these concrete methods and principles such as data smoothing, fitting, reconstructing ,elimi- nating and so on. The example and result about computer processing of 3- D surface shape data are given .