Basic Concepts of 3D Laser Scanning

3D Laser Scanning
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3D Laser Scanning
Technology has significantly transformed the way humans undertake various activities. For example, the introduction of three-dimensional (3D) laser scanners is crucial in many industries, such as healthcare, construction, engineering, manufacturing, and aviation. In particular, 3D laser scanning entails the use of non-contact technology to digitally capture the physical size and shape of objects using laser light. A line of laser light is used to measure the geometry of an object (BuiltEvolve Channel, 2021). 3D laser scanners can capture the dimensions of any object regardless of its size, shape, and features. When capturing the precise size and shape of an object, it is not physically touched. The scans obtained are used to generate a 3D model of objects using imaging software. The paper focuses on the basic concepts of laser scanning, its application in the built environment, step-by-step procedure for capturing laser scans, and post-scan process for converting a point cloud into a reusable building information model (BIM). In addition, it will show how robotic dogs can be used in autonomous laser scanning.
Basic Concepts of Laser Scanning and how it Works
The primary objective of 3D laser scanning is to capture the exact shape and size of a physical object and generate a 3D model. The 3D laser scanner uses a line of laser light that measures the accurate dimensions of an object. Indeed, it combines the distance and direction to calculate the X, Y, and Z coordinates of specific points (Wang & Feng, 2016). For an individual to capture the exact dimensions of a small object, a rotary table is used. Figure 1 below shows how 3D laser scanners capture the size and shape of small objects. 


Figure 1: How 3D Laser Scan Captures the Dimensions of Small Objects (Source: https://matterandform.net/blog/how-do-3d-scanners-work?d)
As shown in Figure 1, the line of laser light is used to capture the object’s dimensions on a rotary table. The object is rotated until all its dimensions are recorded. The data from the laser light is recorded by a digital camera, creating a point cloud of the object’s surface. Figure 2 shows how an object’s shape and size are measured and recorded.


Figure 2: How 3D Laser Scan Generates an Object’s Size and Shape (Source: /figure/The-principle-of-3D-laser-scanning-The-workflow-of-3D-model-construction-based-on-TLS_fig4_306278163)
3D laser scanners usually use infrared, light detection and ranging (LIDAR), or photogrammetry. In particular, LIDAR uses light beams array to calculate the delay that occurs from the reflection of each beam. When time delays are converted into the distance and divided by light speed, a 3D model of an object is created (McManamon, 2015). In addition, Leica ScanStation P50 is the best, safest, and fastest for long-range 3D laser scanning. Unlike other methods, it can be used to scan inaccessible places, such as skyscrapers, from a safe position, reducing time spent in the field. Figure 3 below shows an architect using Leica ScanStation P50 to generate a 3D model of buildings under construction.


Figure 3: The Application of Leica ScanStation P50 to Generate 3D Model of Buildings (Source: https://leica-geosystems.com/products/laser-scanners/scanners/leica-scanstation-p50).
FARO Focus Laser Scanners are used to create accurate, photorealistic, and complete 3D images of objects or environments within a few minutes. Figure 4 below shows a FARO Focus Laser Scanner. Consequently, 3D laser scanning has revolutionized the way objects are digitally captured in multiple industries, such as construction, architecture, and engineering.


Figure 4: FARO Focus Laser Scanner (Source: /en/Products/Hardware/Focus-Laser-Scanners)
Application of Laser Scanning in the Built Environment
Specifically, 3D laser scanning application in the construction sector improves quality and accuracy, cut cost associated with traditional mapping methods, and offers immediate information. In the construction industry, laser scanning is used in buildings design, renovations, clash detection, and construction coordination (Construction Junkie, 2020). Some of its benefits include improving accuracy, design, better coordination and collaboration of primary stakeholders on the construction site, and promoting worker safety. Recently, the demand for quality, accurate, and understandable information has been rising within the construction, engineering, and architectural domain (Dinis et al., 2020). Figure 5 below shows the benefits of using laser scanning in the construction industry.


Figure 5: Benefits of Laser Scanning in the Construction Industry (Source: /publication/301956382_Role_of_BIM_and_3D_Laser_Scanning_on_Jobsites_from_the_Perspective_of_Construction_Project_Management_Personnel)
Kasim Alomari, Michael Olsen, and John Gambatese developed a survey consisting of 50 questions regarding the use of laser scanning and BIM in the construction sector. The online questionnaires were sent to over 200 managers and engineers on different construction sites in the Northwest Pacific. About 56% of the participants depicted that laser scanning is vital in generating 3D models (Alomari et al., 2016). Other benefits of laser scanning in the construction sector, as indicated in Figure 5 include facilitating effective communication between stakeholders, resolving errors that might occur when taking measurements, taking height measurements, and increasing workers’ safety. As such, 3D laser scanning has significantly contributed to numerous benefits in the construction industry.
Step-by-Step Procedure for Capturing a Laser Scan
The following is the procedure of laser scanning in a construction environment (Foster, 2018):
1. Setting up a tripod.
Extend the tripod’s legs and ensure that it is stable and firmly positioned. Then, adjust the tripod based on the object you want to scan and lock its legs.
2. Mounting the scanner.
Mount the scanner on the tripod. At this juncture, one should ensure that the scanner is tightened and screwed properly (FARO Technologies, 2017). Besides, different types of scanners have distinctive ways of mounting, which is why one should follow the manual that comes with every scanner.
3. Insert the memory card.
Open the memory card slot and insert it correctly. Again, one should follow the manual on how to insert the memory card accurately.
4. Power supply to the sca...