TABLE OF CONENTS
Preface iv
Acknowledgement v
Module 1. Introduction 1
1.1 History of Electronic Distance Measurement 1
1.2 3D Laser Scanning Applications in Land Surveying 10
1.3 Economic Impacts of 3-D Laser Scanning
Applications in Land Surveying 10
Module 1 Questions 12
Module 2. Principles of 3D Laser Scanning 13
2.1 Electromagnetic Radiation 13
2.2 Electromagnetic Propagation Rate and the Index of Refraction 15
2.3 Laser Fundamentals 24
2.4 Electronic Distance Measurement Methods 27
2.5 Terrestrial 3D Laser Scanning System 27
Module 2 Questions 30
Module 3. Factors Affecting 3D Laser Scanning 34
3.1 Atmospheric Conditions 34
3.2 Reflectance (Albedo) 34
3.3 Beam Divergence 39
Module 3 Questions 41
Module 4. Performance of 3D Laser Scanning Hardware and Software 42
Module 4 Questions 44
Module 5. Introduction to RealWorks Survey™ 45
5.1 Introduction 45
5.2 RealWorks Survey Environment 45
5.3 Basic Operations 47
5.4 Registration Module 61
Module 5 Questions 71
Module 6. Point Cloud Registration and Georeferencing 72
6.1 Introduction 72
6.2 2D Coordinate Transformation 72
6.3 3D Coordinate Transformation 74
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6.4 Georeferencing in RealWorks Surveying 76
Module 6 Questions 80
Module 7. Traditional Surveying Flow with PointScape™ 81
7.1 Introduction 81
7.2 Detailed Steps 81
Module 7 Questions 99
Module 8. OfficeSurvey™: Basics and Contour Tools 100
8.1 Introduction 100
8.2 Segmentation and Sampling 100
8.3 Creating Subproject 108
8.4 Creating Contours 113
Module 8 Questions 118
Module 9. OfficeSurvey™: Mesh, Volume, Profile and Cross-Sections 119
9.1 Meshes 119
9.2 Volume Calculation 128
9.3 Profile and Cross-sections 134
Module 9 Questions 141
Module 10. OfficeSurvey™: Image Matching and Ortho-Projection 142
10.1 Image Matching 142
10.2 Creating Ortho-Images from Point Clouds or Meshes (Surfaces) 148
Module 10 Questions 153
Module 11. Modeling and Inspection 154
11.1 Cloud-Based Modeling and the Geometry Modifier Tool 154
11.2 Geometry Creator Tool 161
11.3 Surface to Model Inspection Tool 171
Module 11 Questions 182
Module 12. Exporting Data and Working with AutoCAD Land Desktop 183
12.1 Exporting to DXF Format 183
12.2 Exporting to ASCII Format 186
12.3 Exporting Images 190
12.4 Working with AutoCAD Land Desktop 192
Module 12 Questions 200
Lab 1. Laser Scanning System and Laser Safety 201
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Lab 2. Scanner Setup and Operation Using PointScape™ 210
Lab 3. 3D Scanning Workflow: the Traverse Approach 237
Lab 4-5. 3D Scanning Workflow: the Target Approach 239
Lab 6. Georeferenceing 242
Lab 7-8. Topographical Mapping with 3D Laser Scanning 243
Lab 9-10. Creating Surface, Profiles and Cross-Sections and
Calculating Volumes 246
Lab 11-12. Ortho-Projection, Cloud-Based Modeling and
As-Built Inspection 248
Lab 13. Exporting Data from RWS and Importing from AutoCAD 249
Bibliography 250
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PREFACE
Terrestrial 3D laser scanning is the latest technology in electronic distance measurement.
It can obtain measurements at tens of thousands of points per second. Land surveyors are
adopting the technology because of the dramatic increase in productivities and relative ease for
3-D presentation. Applications of terrestrial 3D laser scanning include topographical surveying,
as-built surveying, facility management, 3D imaging and modeling, forensic investigation,
environmental protection and restoration, historical preservations and architectural design.
Currently there is no textbook dedicated to this subject although some remote sensing and
surveying textbooks do have discussions on it.
This text is intended for students in land surveying and civil engineering related areas
though students in other fields that use terrestrial 3D laser scanning may also benefit. It is
written for a one-semester, 3-units course with two hours of lecture and three hours of lab, using
Trimble™ GX 3D laser scanner, PointScape™ field software and RealWorks Survey™ post-
processing software.
The materials include twelve modules of lectures and thirteen labs.
The first module gives a historical review of the evolution of EDM from Geodimeter to
3D laser scanning and discussions include geodimeter, tellurometer, total stations, GPS, and 3D
laser scanners. A comparison of the two types of 3D laser scanning (airborne and terrestrial) is
given. 3D laser scanning applications as well as its impact on land surveying are discussed.
The second module discusses the theoretical background about how distance is measured
in 3D laser scanning. The impact of temperature, atmospheric pressure and humidity on the
index of refraction are compared using the CFF, Edlen and Ciddor methods. Laser
fundamentals including the lasing process, structure of a lasing device and laser properties are
discussed. The two measurement methods, time-of-flight (TOF) and phase-shift, are explained.
This module ends by discussing the major components of a terrestrial 3D laser scanning system.
The third module discusses two factors affecting the performance of 3D laser scanning:
reflectance (albedo) and beam divergence. The objective is to help students realize the impact of
these factors on measurement range and accuracy of a scanner so that they can plan scanning
operations accordingly. The reflectance of commonly encountered surfaces in scanning such as
soil, vegetation, concrete and asphalt is discussed. The impact of water, organic carbon contents
and surface roughness on surface reflectance is also considered. For beam divergence, beam
diameter as a function of wavelength, initial diameter and distance is studied.
The fourth module is based on a survey of 3D laser scanner vendors about their hardware
and software specifications and performance by the magazine Point of Beginning (POB). The
objective is to give students an opportunity to compare the performance of 3D laser scanners and
associated software from different vendors so that they can make an informed decision when
acquiring a 3D laser scanning system. The survey covered more than 40 aspects on hardware
and around 40 on software.
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Module 5 introduces the RWS environment and the three modules in the software,
namely Registration, OfficeSurvey and Modeling. Basic operations such as displaying the point
clouds and images and performing measurement in the 3D View windows are demonstrated. In
addition, cloud-based registration and target-based registration are discussed.
Module 6 gives students some theoretical background about cloud registration and
georeferencing, mainly coordinate transformations. Students will also learn to use the
Georeferencing feature in RWS
Module 7 shows the steps to perform 3D laser scanning following the traditional
surveying flow with PointScape. A detailed flowchart is presented about the traditional
surveying flow. Detailed field operations of this approach with PointScape are discussed.
Modules 8 through 10 present the OfficeSurvey™ module of RWS. OfficeSurvey
provides the tools for data filtering as well as many data processing functionalities. Some of the
features discussed include segmentation, sampling, subproject creation, contour generation,
profile/cross-section creation, polyline drawing, mesh creation, volume calculation, image
matching, and ortho-projection.
Module 11 covers the Modeling module of RWS. Topics include cloud-based modeling,
geometry creation and geometry modification. The Inspection tool in the OfficeSurvey module
is also introduced.
Module 12 discusses data export and working with AutoCAD Land Desktop. Three
types of exports are discussed in this module: point cloud coordinates to .asc (ASCII) files,
geometries to .dxf files and photo images and ortho-images to .tif files. In addition, the process
of importing .asc and .dxf files into AutoCAD Land Desktop is given in detail.
Labs 1through 4 deal with laser safety, equipment setup and configuration, field
operations and PoinScape™. These four labs do not exactly conform to the lecture modules and
some lecturing is needed in the lab.
Labs 5 through 13 match the lecture modules well and lecturing in the lab is usually
unnecessary. Based on the author’s experience, students prefer to spend more time on hands-on
work in the lab.
At end of each lecture module, a list of questions/problems is given and these can be
assigned as part of the homework.
AKNOWLEDGEMENT
Partial support for this work was provided by the National Science Foundation's
Advanced Technological Education (ATE) program under Award No. 0702995. Any opinions,
findings, and conclusions or recommendations expressed in this material are those of the
author(s) and do not necessarily reflect the views of the National Science Foundation.
The author would like to thank Daniel Torres for assistance in preparing the manuscript
and Abide Tabrizi, Gwen Gee, Tim Redd, Jerry Miller, James Crossfield, Nikos Mourtos,
Akthem Al-Manaseer, Steve Choy, Steve Danner, Ann Johnson, Don Marcott, James W.
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McCoy, Nick Soffiotto, Thomas Taylor and Wei Zhou for their involvement with the NSF
project. The author would also like to acknowledge the support of Trimble Navigation, Ltd .
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