At present, a wide variety of 3D laser scanning systems are in use, with different types and areas of operation. They can be classified in many ways based on different research perspectives and working principles.
3D laser scanning systems can be divided into the following four categories based on operational spatial positions:
Aerial Laser Scanning Systems
These systems are mounted on unmanned or manned helicopters and consist of a laser scanner, imaging device, positioning system, flight inertial navigation system, computer, data collector, recorder, processing software, and power supply.
They can quickly acquire large-scale 3D geospatial data within a short period.
Ground-Based Laser Scanning System
This system uses laser pulses to scan the object under test, enabling large-scale, high-speed, high-precision, and high-density acquisition of the three-dimensional shape and coordinates of the object.
The measurement system can be divided into two categories: one is the mobile laser scanning system, and the other is the stationary laser scanning system.
The mobile laser scanning system operates on a vehicle-mounted platform, composed of a global positioning system, an inertial navigation system, combined with a ground-based three-dimensional laser scanning system.
The stationary laser scanning system, similar to the total station in traditional measurement, consists of a laser scanner and control system, built-in digital camera, and post-processing software.
Unlike the total station, the stationary laser scanning system collects “point cloud” data instead of discrete single-point three-dimensional coordinates.
Its characteristics include a large scanning range, fast speed, high precision, and excellent field operability.
Handheld Laser Scanner
This type of equipment is commonly used to gather three-dimensional data from small objects, typically in conjunction with a flexible mechanical arm. Its benefits include speed, simplicity, and precision.
It finds wide-ranging applications across fields such as mechanical manufacturing and development, product error detection, film and animation production, as well as medicine.
Laser Scanners for Special Applications
Laser scanners, such as those used in caves, are applicable in highly dangerous or inaccessible environments, including underground mining tunnels, karst caves, artificially excavated tunnels, and other narrow, elongated spaces, where 3D laser scanning technology can be utilized for 3D scanning.
3D laser scanning systems can be further classified into the following three categories based on the principles of their distance measurement:
1) Those that use pulsed distance measurement technology, which can reach a measuring distance of several hundred meters or even kilometers.
2) Those based on phase measurement principles, primarily used for medium-ranged scanning measurements. The scanning range is typically within a hundred meters. Compared to devices that use pulsed distance measurement, these have relatively high precision.
3) Those based on the principles of optical triangulation. Scanners using optical triangulation typically work at closer distances, within several meters or tens of meters. They are primarily used in engineering measurements and reverse engineering, achieving high measurement accuracy.