LiDAR point cloud data is changing field operations – Visualization and efficiency realized with LRTK

In construction, civil engineering, and other field sites, operational innovation through the introduction of digital technologies is progressing rapidly. Among these technologies, point cloud data obtained by LiDAR is significantly changing on-site workflows. Three-dimensional measurement, which once required specialized surveying instruments and advanced expertise, can now be achieved using a smartphone combined with simple devices. This article explains in detail what LiDAR point cloud data is, the benefits it brings to field operations, and how visualization and efficiency can be realized using LRTK. Let’s look together at how cutting-edge technologies for “visualization” and “labor saving” are poised to change conventional wisdom on site. Note that the use of LiDAR point cloud data is attracting attention from many quarters as a front line of field DX.

What is LiDAR point cloud data?

LiDAR (Light Detection and Ranging) is a remote sensing technology that measures distances to objects by emitting laser light. By scanning the surroundings with a LiDAR sensor, you can obtain point cloud data, which is a collection of many points that make up the surfaces of objects and terrain. Each point in point cloud data has X, Y, and Z three-dimensional coordinate values (and sometimes color information), forming a three-dimensional model that virtually acts as a digital copy of the real space. It is characterized by its ability to record on-site information including “depth” and “shape” that cannot be fully captured by conventional two-dimensional drawings or photographs.

Point cloud data can be obtained by 3D measurement using laser scanners or by photogrammetry, which reconstructs 3D models from photographs. In recent years, in addition to high-performance laser scanners, the latest smartphones and tablets have begun to include small LiDAR sensors, making point cloud acquisition more accessible. For example, using the LiDAR built into higher-end iPhone models, you can hold up the smartphone and instantly scan nearby space to obtain 3D point clouds within a few meters.

The attention on LiDAR point cloud data is backed by the construction industry’s advancing DX (digital transformation) and initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism–led i-Construction, which promote the use of 3D technologies. By digitally recording the entire site and using ICT to improve productivity and ensure quality, point cloud data is becoming a key element of on-site DX. Of course, point cloud data contains a vast amount of information from a single measurement, but improvements in PC and cloud service performance have made processing and sharing large-capacity data easier. With this favorable environment, the utilization of 3D point clouds is becoming the new norm on site. So, what concrete advantages does this LiDAR point cloud data bring when used on site?

Benefits of LiDAR utilization for field operations

Utilizing point cloud data from LiDAR on site provides various benefits that were not possible before. Here are the main points.

• Intuitive 3D visualization: Using point cloud data, site conditions can be visualized as realistic 3D models. Displaying colored point clouds on a screen recreates scenes much like photos or the real thing, making the space easier to understand at a glance even for newcomers or clients who struggle with reading drawings. Height differences and shapes that are hard to grasp on flat drawings can be understood intuitively, which also facilitates smoother communication.

• Rapid measurement and data acquisition: LiDAR scans allow you to acquire extensive current-condition data in a short time. By walking while emitting laser light, one scan can automatically acquire hundreds of thousands of measurement points. For example, for a development site about 50 m square (164.0 ft square), you can imagine obtaining the point cloud of the entire terrain in just a few minutes by walking with a smartphone. Traditionally, surveying staff measured points one by one, requiring manpower and days to cover a wide area, but with LiDAR a single person can measure the entire site at high density in a short time. The significant reduction in required personnel and dramatic shortening of work time are major efficiency benefits.

• High-precision measurement: On the obtained point cloud data, you can freely measure distances between any two points, areas, volumes, and so on. Compared with traditional on-ground scaling methods, this is markedly more accurate and reduces the risk of human error. Fine dimensions and inclination angles between measurement points can be calculated digitally, improving quality control and as-built verification accuracy.

• Comprehensive data and reuse: Once acquired, a point cloud contains enormous information covering every corner of the site. Therefore, even if you notice later that you “forgot to measure another spot,” additional analysis or checks can be performed on the point cloud data. You can extract cross-sections later or overlay measured data onto a design 3D model to check for discrepancies, making secondary use easy. Point cloud data becomes a digital archive that records the site as a whole, useful for future renovation planning and maintenance management.

• Improved safety: Because LiDAR can measure without contact, there is no need to enter dangerous areas unnecessarily. You can scan and obtain data from a safe distance for unstable slopes, high places, or areas with vehicle traffic. The need for additional personnel to perform safety checks is reduced, and high-risk field tasks can be completed with a minimum crew. As a result, it contributes to both worker safety and labor reduction.

As described above, leveraging LiDAR point cloud data enables both “visualization of the site” and “operational efficiency and sophistication” simultaneously. Now let’s look at concrete examples of the field tasks where this point cloud data is proving useful.

Field use cases of LiDAR point cloud data

Point cloud data obtained by LiDAR is being used in a variety of field operations in construction and civil engineering. Here are some representative use cases.

• Surveying current terrain: Point cloud data is powerful for surveying sites and terrain before construction begins. Traditionally, surveyors observed key points one by one with total stations and other instruments, reading elevations to create topographic maps. Using LiDAR scans, you can scan the ground surface as an area to quickly obtain a detailed terrain model. Even for undulating or complex terrain, you can comprehensively digitize the site, enabling efficient earthwork calculations and design review. Detailed 3D terrain models generated from acquired terrain point clouds can also be used as explanatory materials for clients and for planning construction.

• As-built verification: This method measures entire completed structures or developed land with point clouds to verify that they conform to the design. If you record completed structures thoroughly with point clouds, you can later verify cross-sectional shapes and slopes. Traditionally, only key dimensions were measured and recorded, but with point cloud data you can store the entire finished object as 3D data, improving inspection reliability and aiding future renovation planning.

• Construction management (progress and quality control): Point cloud data is also useful during construction. For example, if you scan the site weekly or at key stages, you can quantitatively grasp the volume of fill or excavation. Calculating volumes from point clouds enables accurate management of transported soil quantities, and checking discrepancies against the design model at each phase prevents rework. Comparing point clouds over time allows you to visually capture construction progress, making it easier for stakeholders to share a common understanding.

• Infrastructure inspection and maintenance management: Point cloud data is used for routine inspections of bridges, tunnels, road slopes, and other infrastructure. If you scan structures at regular intervals and accumulate the data, you can compare changes digitally over time. You can objectively detect signs of crack propagation or deformation, providing material for preventive maintenance and repair planning. LiDAR measurement enables efficient and safe work even in high places or at night, where human access is difficult. Inspections that previously required work vehicles or scaffolding and visual checks can now obtain high-precision data remotely, leading to labor and sophistication gains in inspection work.

• Construction simulation and consensus building: Using point cloud data and design 3D models, simulation of construction plans and stakeholder consensus building are becoming possible. For example, overlaying a model of the planned completed structure onto the site point cloud or actual scenery allows intuitive sharing of the expected final appearance before construction starts. Design intent that is hard to convey with drawings alone is visualized in 3D, making explanations to clients and local residents smoother and helping prevent construction mistakes. Combined with AR (augmented reality) technology, you can visualize temporary yard layouts or the locations of underground utilities on site, assisting safer and more optimal planning.

As described above, LiDAR point cloud data is beginning to be used across a wide range of tasks from surveying to construction and maintenance. Supporting these uses are the recent mobile LiDAR measurement solutions that make acquisition easy. One such solution is LRTK. Next, let’s see how using LRTK can realize on-site visualization and efficiency.

Realizing visualization and efficiency with LRTK

LRTK (pronounced “el-are-tee-kay”) is an innovative solution that turns a smartphone into a high-precision 3D surveying instrument. Developed by a startup spun out from Tokyo Institute of Technology, it consists of an add-on ultra-compact RTK-GNSS receiver (positioning device) that attaches to a smartphone or tablet. It can be attached to the back of a phone with a one-touch action and, once wirelessly connected, is ready to use. Without complex operations, anyone can perform high-precision positioning and point cloud scanning with their own smartphone.

When performing point cloud scans with a smartphone’s built-in LiDAR alone, walking over a wide area can cause accumulated sensor errors and gradual positional drift that distorts the acquired point cloud. Also, because absolute coordinates (latitude/longitude and elevation) are not attached to each point, it is difficult to integrate the data later with other survey data or to show accurate positional relationships on drawings. LRTK solves this problem. Its built-in RTK-GNSS receiver continuously determines the smartphone’s position in real time with centimeter-level accuracy and assigns global coordinates to each point acquired by LiDAR. As a result, no matter how widely you scan a site continuously, the entire point cloud is recorded in a consistent coordinate system. The measurement range that was limited to a few meters with a smartphone alone expands to tens to hundreds of meters, enabling large-scale 3D measurement of sites in a single session.

Mobile point cloud measurement using LRTK brings various benefits that transform field operations. First, measurement can be completed by a single person. You simply walk while holding the LRTK device and a smartphone—there is no need to carry heavy tripods or prisms. Device setup takes only a few minutes, removing the need to allocate multiple team members for surveying. Next is increased measurement efficiency. Automatic point cloud acquisition by LiDAR combined with immediate high-precision positioning by RTK dramatically speeds up surveying tasks that previously took days. As mentioned earlier, a scan that can be completed in about 5 minutes for a site of approximately 50 m square (164.0 ft square) would have required many times the planning, observation, and recording time and manpower with traditional manual surveying. Moreover, with LRTK there is no need for post-processing adjustments such as aligning reference points to the obtained point cloud. Data is automatically saved on site as accurate, coordinate-attached data, so you can immediately use it for volume calculations or drawing creation after scanning. There is no need to copy numbers into paper field books; all data is digitally recorded to the cloud and can be shared in real time with staff in the office.

In terms of ease of visualization, point clouds obtained with LRTK can be immediately displayed and checked in 3D on a smartphone or PC. You can survey the terrain you just scanned on site and, if you find omissions, perform additional measurements immediately. If necessary, you can overlay design drawings or equipment models in AR to perform on-site as-built comparisons and verification.

Another major attraction is the low introduction cost. Traditionally, equipping centimeter-level accuracy 3D surveying instruments required investments on the order of millions of yen, but because LRTK leverages a simple smartphone-based design, it can be introduced at a much lower cost. Prices are affordable enough that deploying one per staff member on site becomes a realistic option. If each person can perform surveying and recording with LRTK when needed, overall team productivity will dramatically improve.

With the application of LRTK, surveying processes on site can be greatly simplified and labor reduced. It combines ease of use that even non-experts can handle with high accuracy, enabling high-quality surveying and measurement even with limited personnel. Work time in hazardous areas is shortened and safety is enhanced. In short, an environment in which “anyone, anywhere, immediately” can obtain and utilize 3D site data is taking shape.

Conclusion: The revolution LiDAR point cloud data brings to field operations

LiDAR point cloud data is poised to fundamentally change how field operations are conducted. Three-dimensional visualization makes it easier to grasp site conditions and share information among stakeholders, while efficient data acquisition can greatly reduce work time and manpower. Surveys that once required multiple people and heavy equipment can now be completed quickly by a single person using only a smartphone and LRTK. As a trump card for productivity improvement and workstyle reform in surveying and construction management, the use of LiDAR technology will become increasingly important. Advances in sensor technology and cloud services will make on-site data utilization even more accessible and sophisticated in the future.

Simple field surveying no longer requires special expertise or expensive equipment. By simply combining a smartphone with LRTK, anyone can easily acquire high-precision point cloud data and immediately use it for on-site surveying and measurement. Adopting these methods makes previously unseen aspects “visible,” leading to smarter field operations with less waste and fewer hazards. Why not explore the future of your site with the power of LiDAR point cloud data and LRTK?