APPLICATION OF LASER SCANNING TECHNOLOGY FOR DIGITAL MODELING OF OBJECTS ON THE EARTH'S SURFACE

ABSTRACT

This article explores the use of three-dimensional laser scanning for acquiring digital data of surface objects. In recent years, this technology has been increasingly applied in Uzbekistan due to its high precision, speed, and user-friendliness. The paper covers both terrestrial and aerial survey methods, highlighting their role in the creation of digital maps and topographic plans. The operational principles of laser scanners are described in detail, including distance calculation, coordinate registration, and real-time 3D model generation. Special attention is given to the application of laser scanning in civil construction, engineering geodesy, and cadastral projects. The study emphasizes that laser scanning enables millimeter-level measurement accuracy without the need for reflectors or additional equipment, while significantly automating labor-intensive geodetic tasks. The use of laser scanning is positioned as a key element in improving the quality of engineering projects and in enabling efficient spatial data management.

АННОТАЦИЯ

Статья посвящена применению трёхмерного лазерного сканирования для получения цифровых данных об объектах на поверхности земли. В последние годы данная технология получила широкое распространение в Узбекистане благодаря своей высокой точности, скорости и удобству в использовании. В работе рассматриваются как наземные, так и воздушные методы съёмки, а также их роль в создании цифровых планов и карт. Подробно описан принцип действия лазерных сканеров, включая расчёт расстояний до объектов, регистрацию координат и формирование трёхмерных моделей в режиме реального времени. Особое внимание уделено использованию лазерного сканирования в гражданском строительстве, инженерной геодезии и кадастровых работах. Отмечено, что данная технология позволяет получать миллиметровую точность измерений без применения отражателей и других дополнительных устройств, а также обеспечивает автоматизацию трудоёмких геодезических процессов. Применение лазерного сканирования рассматривается как ключ к повышению качества проектных и строительных работ, а также к устойчивому управлению пространственными данными.

Keywords: laser scanning, 3D modeling, geodetic survey, digital terrain model, terrestrial scanning, LiDAR, coordinate system, engineering geodesy, cadastral works.

Ключевые слова: лазерное сканирование, 3D-моделирование, геодезическая съёмка, цифровая модель местности, наземное сканирование, LiDAR, координатная система, инженерная геодезия, кадастровые работы.

Introduction. In recent years, the application of three-dimensional laser scanning technologies has seen a remarkable rise in various fields, including architecture, geodesy, mining, archaeology, construction, and environmental monitoring. This growing popularity is largely due to the ability of these scanners to rapidly and accurately collect vast amounts of spatial data, all while maintaining a high level of detail and precision. The technology enables users to capture millions of points on the surface of an object or structure, producing what is known as a “point cloud,” which serves as the basis for building detailed 3D models [1-8].

Materials and methods. Three-dimensional laser scanning provides digital information about the object, in addition to its real-time location and coordinate points in the specified coordinate system. The process also yields an image of the object's surface during the measurement process. The utilization of laser scanners in photogrammetry engenders numerous advantages in the deciphering of the obtained images. The enhancement in the quality of the resulting digital model, photomap and plans of the territory is also a notable benefit. Surface laser scanners are utilized to obtain precise information regarding the intricacies of construction structures and engineering objects, in addition to creating their three-dimensional models. Examples of such objects include bridges, overpasses, pipelines, power lines and tunnels.

Laser scanners are utilized to scan not only the exterior of buildings but also their interior. Consequently, a digital model of the entire building, including both interior and exterior elements, is created. The operational principle of a laser scanner is analogous to that of a laser rangefinder. The laser emits laser pulses of a higher frequency than itself (emitting ten thousand pulses per second) [2].

The pulses are directed towards the object and, upon striking it, are reflected and subsequently imaged by highly sensitive receiving equipment.

This process enables the determination of the distance from the scanner to the object. D = 0.5 *v* t,

Where: v- is the propagation speed of the pulse, and t - is the time it takes for the pulse to travel to the object and return. Concurrently, the optical beam is imaged in the vertical and horizontal planes using a servomotor, which means scanning the surface of the object.

Figure 1. Geodetic survey

Results and discussion. The angle of the laser beam in the coordinate system is recorded in both the horizontal and vertical planes by the scanner equipment. The coordinates of these points are then calculated using the following formula.

In instances where it is necessary to accept these coordinates in another coordinate system, the following formula is employed:

where - are the initial coordinates of the scanner coordinate system; for example, these can be geodetic or systematic coordinates of the object. In the majority of cases, GPS equipment and electronic total stations are utilized to establish a connection between the scanner coordinate system and the primary coordinate system.

It is also noteworthy that contemporary scanners can execute the functions of an analog total station. The structure of the two-axis compensator endows scanners with full control over surveying processes at their installed point [1-4].

In the contemporary context, the judicious selection of a computer program that is optimally suited to the task of processing the results obtained from a surface scanner is of paramount importance. When computer programs are employed to create a 3D model of an object and a digital 3D cadaster of a site, the selected program must be capable of "completely recording the point cloud" and "creating a three-dimensional model of the site, profile, and sections using primitives."

Scanning is a method that has achieved significant success in the automation of numerous geodetic productions. It facilitates the creation of complex surveys and is an indispensable method in human life, allowing for the rapid completion of tasks with the simple press of a button. However, when it comes to the surveying of complex objects, a work plan must be formulated, and surveying at several points is necessary. Consequently, the surveying process furnishes exhaustive information regarding the object at a rate one hundred times faster than other methodologies [1-8].

Figure 2. Scanning operation

Conclusion. In conclusion, it can be asserted that the terrestrial laser scanning method is distinctly different from other methods of collecting spatial data. The following three indicators demonstrate this distinction: Firstly, the acquisition of comprehensive information about the object without the use of reflectors or additional equipment at a specific distance from the object. Secondly, the attainment of information about the object with millimeter precision is a feat unparalleled by other methods. Thirdly, the measurement of distances of several thousand meters per second from behind.

The versatility of laser scanning, coupled with its high degree of automation, facilitates the resolution of numerous engineering challenges. The utilization of laser scanning in construction projects is poised to experience a significant surge in demand, thereby facilitating the introduction of ground power.

References:

1. Boehler, W., Bordas Vicent, M., & Marbs, A. (2003). Investigating laser scanner accuracy. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 34(5), 696–701.
2. Jumanov B.N. The importance of space images in updating agricultural maps and plans (on the example of the brick massif of Kamashi district) 2022/3/30 International conferences on learning and teaching 261-264
3. Jumanov B.N. The process and methods of increasing students' activity in teaching geography 2022 Science Bulletin 18-22
4.  Kersten, T., & Lindstaedt, M. (2012). 3D laser scanning for heritage documentation: New perspectives for cultural heritage. Journal of Cultural Heritage, 13(4), 430–435.
5. Murtazin, R. I., Abdullin, I. I. (2021). Application of LiDAR Scanners in Engineering Geodesy. Geodesy and Cartography, (8), 22–27.
6. Reshetyuk, Y. (2009). Self-calibration and direct georeferencing in terrestrial laser scanning. KTH Royal Institute of Technology.
7. Vasiliev, S. V. Geodesy and Laser Scanning: A Textbook. Moscow: MGSU Publishing, 2020. — 256 p.
8. Vosselman, G., & Maas, H. G. (2010). Airborne and terrestrial laser scanning. CRC Press.