Capturing and Modeling Reality in 3D
LiDAR-based laser scanning is a technique that changed how humans model and understand their environment forever. This article introduces LiDAR technology, highlighting its applications, limitations, and benefits across various industries. We focus on its impact in the AEC industry through several case studies.
The basics of LiDAR technology explained
LiDAR (or laser scanning) is a method that uses laser pulses to measure variable distances to the immediate surroundings. Different types of laser scanning all use the same technology, which consists of a lidar unit to emit laser pulses or photons that bounce back to the lidar sensor after hitting a target. A lidar system records data from that return, such as the distance to the target and return time.
Using the speed of light, it is possible to calculate the distance between the lidar unit and the target. A laser scanner can send out hundreds of thousands of beams per second. This enables distinguishing objects in the environment, similar to human perception.
Combined with a GPS unit, a laser scanner “knows” where objects in their immediate surroundings are located. All recorded, individual laser returns are recorded and stored digitally at the moment of capture, so they can be visually represented as a 3D point cloud that provides the basis for an accurate and textured 3D representation of the data using specialized software.
Uses in laser scanning applications
LiDAR technology, a cornerstone in laser scanning applications, has revolutionized our approach to capturing and modeling the physical world in 3D. Its versatility is evident in various specialized applications, each tailored to fulfill specific requirements. Here’s a more structured and detailed explanation:
Airborne LiDAR
This variant is predominantly used for topographical mapping and studying natural features. For instance, it plays a crucial role in analyzing tree canopy structures. The detailed 3D terrain models generated from airborne LiDAR are invaluable for utility companies. They utilize these models to ensure that power lines are not encroached upon by vegetation, thereby maintaining safety and operational efficiency.
Bathymetric LiDAR
This type of technology specializes in aquatic environments. It’s instrumental in measuring and charting water depths, both along coastal regions and within river systems. By employing this technology, researchers and planners can obtain precise underwater topography, crucial for marine navigation, coastal management, and environmental studies.
Terrestrial LiDAR
This category includes both static and mobile laser scanning:
- Static Laser Scanning: Primarily used in surveying, static terrestrial LiDAR captures comprehensive 3D representations of areas or structures. It’s commonly employed in architectural and archaeological documentation, where precise spatial measurements are vital.
- Mobile Scanning Technology: Gaining rapid popularity, mobile LiDAR systems are essential in dynamic environments. These systems are extensively used for monitoring construction projects and capturing detailed interiors of complex structures like mines or caves. Their mobility offers significant advantages over traditional, heavier 3D scanners, particularly in terms of ease of transport and operational flexibility.
Beyond these specific applications, LiDAR’s scope extends to various other domains. Environmental scientists leverage LiDAR to measure atmospheric pollution levels, contributing significantly to climate research. In urban settings, LiDAR-based speed guns are a common tool for traffic law enforcement, showcasing the technology’s adaptability.
In summary, LiDAR plays a multifaceted role in laser scanning, addressing a variety of needs such as precise surveying, topographical mapping, environmental monitoring, and urban management. Its continuous evolution and integration into different fields are a testament to its transformative impact on how we perceive and interact with our 3D world.
Benefits of LiDAR in laser scanning
There are many benefits, which explains why so many different industries are using it:
- Unlike cameras, lidar works well for capturing data in the dark. This explains for a large part the interest from the automotive industry in lidar;
- The scan data are very accurate, meeting surveying precision requirements, resulting in high-resolution 3D maps;
- The data capture process is very quick, saving end users time and money when compared with other data acquisition types;
- Another great benefit is that data acquisition happens almost automatically: with a single button push, a scanner can be activated without any prerequisites from the operator.
Combined with a decrease in prizes and increases in the potential of lidar sensors, powerful and affordable laser scanners have become accessible to a wide group of end users, and this development is expected to continue: the market for laser scanning is expected to reach $16.66 billion by 2030, according to this resource.
Exploring Some Limitations
1. Weather Sensitivity
One of the primary limitations of LiDAR is its sensitivity to weather conditions. Elements like rain or snow can significantly hinder the quality of data capture by altering the reflectance and scattering of the laser pulses. This factor often confines LiDAR operations to clear weather conditions, impacting the scheduling and feasibility of outdoor scanning projects.
2. Data Processing Speed
In scenarios where real-time data analysis is crucial, such as autonomous vehicle navigation, the processing speed of LiDAR can be a critical bottleneck. Although LiDAR captures detailed 3D data efficiently, this data requires extensive processing and mapping before it becomes actionable. This delay is pivotal in situations demanding instant interpretation of the surroundings.
3. Cost Implications
The high cost of LiDAR systems is a significant limitation for budget-constrained or smaller-scale projects. This expense encompasses not just the initial purchase, but also ongoing maintenance, software for data processing, and the need for skilled personnel for operation and analysis.
4. Survey Control and Accuracy
Achieving high accuracy in LiDAR scanning depends on having precise survey control. It is crucial to ensure meticulous calibration and alignment because even small deviations can result in inaccuracies. Moreover, the precision limitations of LiDAR systems can pose a challenge in applications that require ultra-precise measurements
Achieving high accuracy in LiDAR scanning depends heavily on having precise survey control. It is crucial to ensure meticulous calibration and alignment, as even minor deviations can lead to significant inaccuracies in the final data. Additionally, it’s important to recognize the inherent precision limitations of LiDAR systems. These limitations can pose challenges in applications that demand ultra-precise measurements, necessitating careful consideration of the equipment’s capabilities relative to the project requirements.
5. Drone-Based LiDAR Challenges
- Weight Constraints: The limited carrying capacity of drones restricts the size and weight of LiDAR systems they can transport. This limitation often necessitates a compromise between the drone’s flight duration and the quality of the LiDAR system.
- Operational Risks: Employing drones for LiDAR scanning introduces risks like potential crashes or loss of control due to adverse weather conditions. Combined with the high costs of LiDAR equipment, these factors make drone-based operations a cautious choice.
- Regulatory Restrictions: Drone flights, particularly in urban or sensitive areas, are subject to strict regulations. Obtaining permissions can be challenging, with the legal landscape varying widely across regions, adding complexity to drone-based LiDAR projects.
6. Shipping and Handling Complexities
- Logistical Challenges: Shipping LiDAR equipment, particularly the more sophisticated and larger systems, involves complex logistics. The need for specialized packaging to protect delicate components adds to the overall cost and complexity of transportation. Environmental Impact: The transportation of heavy LiDAR equipment, especially over long distances, has an associated environmental cost, including a carbon footprint that must be considered in project planning.
By comprehending these limitations, professionals in the field can better strategize the deployment of LiDAR technology. This ensures not only optimal results but also a thorough navigation of its constraints.
Industries that use LiDAR-based laser scanning
While LiDAR originated in science to study the earth’s atmosphere and weather, other industries developed applications and systems that use lidar-based laser scanning. As a remote sensing technology, airborne lidar became a popular way to capture additional spatial data to study the earth’s surface. The same goes for the surveying industry, where 3D laser scanners proved a quick way to produce high-quality maps of the built environment.
High-end 3D laser scanners are also found in preservation work such as cultural heritage or forensics, to quickly capture the scene of an accident and reproduce that digitally for extended analysis.
The automotive industry is probably the industry that is eager to monetize on the promise of lidar-based laser scanning, not only to produce a real-time 3D map of all highways on earth but also to help realize assisted-driving systems where a car can navigate itself or react to its environment based on combined scanning data from a fleet of nearby cars.
Finally, a central industry for the use of laser scanning is the AEC industry. It enhances planning, operation, and monitoring of construction projects, both remotely and onsite. Using laser scanners reduces costly shutdown times. It allows planning and executing retrofits with as-built data, leading to efficient management of large projects.
Laser scanning also improves daily progress tracking and job site safety by eliminating manual measurements. The precise scan data aids in as-built inspections and modeling. It’s used to create various outputs, like floor plans and elevation drawings.
Conclusion
Lidar-based laser scanning is a technique to model and capture the environment in 3D. It is has quickly become the ‘to-go’ solution for many applications and industries, due to its ease of use, the resulting highly accurate scan data and its fast data acquisition process. The AEC industry in particular has been able to exploit the different benefits of the technology, as the data can be captured and used for different use cases that all provide instant value to different stakeholders. To help AEC professionals choose a laser scanning provider that best suits their needs, the Sirvey platform was created.
Sirvey has a network of pre-qualified laser scanning providers, selected through careful evaluation of their technical capabilities, experience, equipment, and reputation in all major US markets. This enables AEC professionals to save on travel costs, get quicker responses, and find the most cost-effective laser scanning solution tailored to their specific needs.
