As a high-precision, non-contact measurement method, laser scanning technology has been widely used in fields such as architecture, surveying, archaeology, and industrial manufacturing in recent years. It quickly obtains three-dimensional spatial information of the target object's surface by emitting laser beams and receiving reflected signals, thus generating high-precision point cloud data. This article will briefly introduce the basic principles of laser scanning technology and its data acquisition process.



The core principle of laser scanning technology is the 'time-of-flight' method (TOF) or phase difference method. The time-of-flight method calculates the distance between the scanner and the object being measured by measuring the time difference from the emission to the reception of the laser pulse. The phase difference method obtains distance information by emitting modulated laser light and comparing the phase difference between the reflected light and the original light, which is suitable for short-distance, high-precision measurements. Both methods combine horizontal and vertical scanning mirrors to achieve a comprehensive scan of three-dimensional space.



Specifically, laser scanners emit laser beams to the target area at certain angular resolutions and scanning rates while working, and receive the reflected signals through the receiver. For each laser beam emitted, the system records the distance, angle, and reflectance intensity information of that point. Through the rotation of the scanner or the simultaneous operation of multiple laser beams, a large number of three-dimensional coordinate data points can be obtained in a short time, forming what is known as 'point cloud' data sets.



Point cloud data not only contains spatial coordinates (X, Y, Z), but can also combine color information (through synchronized photography) or reflectance intensity information to further enhance the expressiveness of the data. These raw data are processed in later stages, such as denoising, alignment, and modeling, to generate 3D models, planar maps, or cross-sectional maps, which are widely used in fields such as building modeling, terrain surveying, and cultural heritage digital protection.



In addition, laser scanning technology is divided into various forms such as ground laser scanning, airborne LiDAR (Light Detection and Ranging), and handheld laser scanning, which meet the data collection needs in different scenarios. For example, in urban 3D modeling, airborne LiDAR can obtain large-area terrain and landform data in a short time; while in precision component inspection, ground or handheld scanners are more commonly used to ensure accuracy.



In summary, laser scanning technology, with its advantages such as high efficiency, accuracy, and non-contact, has become an important tool for modern data collection. With the improvement of hardware performance and the optimization of software algorithms, its application range will continue to expand, providing more convenient and reliable data support for all industries.