Infrared Visual Inspection DX: Streamline Inspection Work with LRTK and Simplify Report Creation

To detect deterioration on building exterior walls and rooftops early and ensure safety, the use of infrared visual inspection is indispensable. This non-destructive testing method using an infrared thermography camera measures the temperature distribution on a building surface from a distance and is characterized by its ability to visualize internal voids and moisture-related anomalies. Because it can inspect high places without erecting scaffolding, it is safer and, thanks to its efficiency in checking wide areas in a short time, has been increasingly adopted for regular inspections of medium- to large-scale facilities such as condominiums, public facilities, factories, schools, and commercial buildings. However, conventional infrared inspections have left issues in how investigation results are recorded and shared. It has been difficult to convey the exact location of anomalies, and report preparation has required considerable effort and time, leaving a heavy burden on site teams.

One innovative on-site DX tool attracting attention is “LRTK”, which combines a smartphone with a compact positioning device. When LRTK is combined with infrared visual inspection, anomaly locations can be accurately recorded with coordinates, and their spatial relationships can be intuitively understood on-site via AR navigation and 3D model display. Inspection data are shared to the cloud immediately, making internal and external information sharing and report creation easy. This article reviews the outline of infrared visual inspection and the challenges of conventional methods, then explains in detail the main functions of LRTK and how it integrates with infrared inspections. It also touches on the improvements in accuracy for re-inspection and repair instructions enabled by coordinate recording, the effects of visualizing reports using point cloud data and AR, the operational efficiency gains observed in actual implementation cases, and concludes by summarizing LRTK’s potential to spread not only as a complement to infrared inspection but also as a daily inspection tool.

What is Infrared Visual Inspection? — Visualizing Internal Anomalies Non-Contactly

Infrared visual inspection is an inspection method in which the infrared (thermal radiation) emitted from a building’s exterior surface is captured by a specialized camera, and anomalies inside the wall are detected from the temperature distribution. By capturing temperature changes after the exterior wall or rooftop has been heated by the sun, deterioration invisible to the naked eye—such as internal voids, delamination, and water ingress points—can be visualized in images. For example, parts where exterior tiles have detached from their substrate or areas where water has penetrated concrete internal layers will cool at different rates after sunset compared to sound areas, and thus appear as temperature non-uniformities (thermal anomalies) on infrared images.

A major advantage of this inspection using infrared thermography is that it is non-contact and non-destructive. If photographed from a distance with a high-magnification lens or a drone-mounted camera, even high exterior walls can be inspected without scaffolding, enabling far-reaching checks in a single pass that are safer and lower-cost compared to traditional tapping inspections. In practice, for exterior wall inspections under the periodic report required by Article 12 of the Building Standards Act (so-called Article 12 inspections), the conventional method was for a qualified person to tap the entire exterior with a hammer, but recently infrared cameras have drawn attention as an efficient diagnostic method. Infrared visual inspection, which can survey without erecting scaffolding in a short time, has been increasingly used for pre-major-repair surveys of condominiums and buildings, contributing to reduced repair costs through early detection and labor savings in inspections.

However, detecting anomalies by infrared visual inspection is not the goal itself; subsequent recording and reporting are critical. Thermography images show defective areas as temperature differences, but unless you accurately convey “where on the building that is” and “how large the affected area is,” the findings cannot be utilized for repairs or continued monitoring. Conventionally, after locating suspicious areas in infrared images, inspectors would mark them on-site with chalk or tape or hand-draw the shooting positions on drawings. But this method left issues such as ambiguity in conveying positions and cumbersome recording tasks. The next chapter organizes these specific problems of traditional methods.

Problems with Conventional Inspection Methods — Recording Effort, Positional Ambiguity, Reporting Costs

Even if anomalies can be detected with an infrared camera or tapping rod, if conventional recording methods remain analog-centered, valuable survey results cannot be fully utilized. In many actual field cases, inspectors walk around with building drawings (layout plans and elevation drawings) in hand and, whenever they discover an anomaly, circle or number the corresponding location on the drawing with a pen. They simultaneously take condition photos with a digital camera and later reconcile photo filenames with the numbers on the drawing for organization. The conventional methods have the following issues.

• Cumbersome recording work: Managing survey results with drawings and photos takes a great deal of effort and time. Marking drawings, sequentially numbering photos, and transcribing into report formats are all manual tasks, so human errors are prone to occur, placing a heavy burden on on-site personnel. Especially when multiple anomalies are found, staff become swamped with organizing photos and matching numbers, reducing productivity.

• Positional ambiguity of anomalies: Hand-drawn marks on drawings and photos alone have limits in conveying the “exact position” of deterioration. For example, simply circling “a crack found on the north exterior wall” on a drawing makes it difficult to identify the exact height and extent on the actual wall, and viewing a photo alone may make it hard to grasp scale and positional relationships with surroundings. As a result, repair personnel may end up searching on-site thinking “it’s probably around here,” or in the worst case there is even a risk of overlooking areas that require repair.

• Difficulty in longitudinal comparison: When inspection results are managed in a scattered manner on paper and in photos, comparing with previous inspections during the next check becomes difficult. If the method of recording or the way marks were placed on the drawing differs between inspections, it may be impossible to determine whether deterioration occurred at the same location. Also, tracking quantitative long-term changes (for example, how many years and how many cm a crack has grown) is difficult with paper materials, making it hard to accurately evaluate the progression of deterioration.

• Quality of inspection depends on the individual: Tapping surveys and high-place visual inspections of exterior walls rely heavily on craftsmanship, so there tends to be differences in accuracy and risk of oversight between experienced personnel and newcomers. For instance, distinguishing voids from the sound of tapping requires experience, and the size of cracks detectable by binocular-based visual inspection varies by person. Because recording methods are not standardized, the inspection accuracy fluctuates depending on who performs it, making it difficult to ensure “zero oversights.”

As described above, with conventional methods, findings from infrared visual inspection often suffer information loss at the stages of recording and transmission, and operational costs balloon. With the current severe shortage of skilled technicians, maintaining an efficient inspection system using traditional methods is also challenging. How can these issues be solved? One answer is a digital recording method utilizing LRTK. The next chapter introduces the main functions of LRTK and how it links to infrared inspections, offering solutions that break through the limitations of conventional methods.

Main Functions of LRTK and Its Integration with Infrared Inspections

LRTK is a smartphone high-precision positioning and AR system developed by a startup from the Tokyo Institute of Technology. By attaching a palm-sized RTK-GNSS receiver (a GPS device capable of centimeter-level positioning (cm level accuracy, half-inch accuracy)) to a smartphone or tablet and using a dedicated app, this single device enables a variety of on-site features such as positioned photo capture, 3D point cloud scanning, AR marker recording, and cloud sharing. Even without complex equipment or advanced expertise, it is attracting attention as an innovative tool that dramatically improves accurate situational awareness and efficient recordkeeping in building and infrastructure inspection work.

Below are the main LRTK features that are especially powerful when integrated with infrared visual inspection.

• Geotagged photos with high-precision positional information (positioned photos): Photos taken on a smartphone at the site automatically have the shooting position’s latitude, longitude, and altitude coordinates and the camera’s orientation (azimuth) attached. For example, simply taking a photo when you find an anomaly on an exterior wall makes it easy to intuitively grasp “which part of the building the photo shows” afterward. Because the photo itself acts as a map pin, you can avoid tedious tasks like matching photos to drawings or taking notes, and prevent record omissions and mix-ups. If anomalies detected with an infrared thermography camera are associated with visible-light photos that have high-precision coordinate tags, the thermal image can be accurately linked to the actual position later.

• AR marking of anomaly locations: LRTK includes an AR (augmented reality) function that overlays obtained 3D models and drawing information onto the real world. Moreover, because RTK-GNSS provides centimeter-level positioning (cm level accuracy, half-inch accuracy) and constantly maintains highly accurate self-positioning, digital information aligns with the real object without the need for marker placement or manual alignment as in typical AR. When viewing a building through a smartphone or tablet during inspection, 3D models and guidance information align precisely over the actual exterior wall. By tapping the screen on an anomaly, you can place a virtual marker at that location and record the position coordinates instantly. For example, if an exterior tile detachment is identified by an infrared camera, you can point to the corresponding spot in LRTK’s AR mode and place a marker, enabling safe position recording on scaffolding without having to remove your hands. Because these markings are saved as three-dimensional coordinate data, you can reproduce which floor and which part had anomalies later in three dimensions.

• 3D point cloud scanning: The LRTK app leverages a smartphone’s built-in LiDAR sensor or camera to capture the surrounding environment as point cloud data (a set of numerous three-dimensional measured points). By walking around and scanning a building exterior, a high-precision 3D model including wall shapes, cracks, and discoloration can be generated in a short time. The acquired point cloud data are tagged with absolute (geodetic system) coordinates, enabling later overlay with maps or design drawings. Anomalies found in infrared inspections can be plotted on this point cloud model, leaving a comprehensive condition record that includes fine cracks and bulging not visible in thermal images. Point cloud data can be uploaded to the cloud and shared with stakeholders, and even without specialized software it can be viewed, rotated, and zoomed in a browser.

• On-site dimension measurement and area calculation: On the 3D data acquired by LRTK, you can immediately measure the lengths and areas of points of interest. For example, you can trace a crack on the point cloud to measure its length or calculate the area of rust staining, quantifying the scale of deterioration in real time on-site. Tasks that previously required applying a separate scale or calculating on drawings later can now be completed during inspection with a single smartphone, directly improving the accuracy of repair scope estimates and streamlining report preparation.

• Cloud synchronization and sharing: Positional data, point cloud data, and photos recorded with LRTK are automatically uploaded to the cloud and stored securely. It’s a single click to review details on a PC back at the office or to share data with supervisors, colleagues, or clients. Even recipients who haven’t installed a dedicated viewer can view 3D models and photos via a web browser, significantly lowering the barrier to information sharing. Inspection data uploaded to the cloud from the site on the day of the infrared inspection can be immediately reviewed by remote technicians, who can provide advice in real time.

With these features, LRTK brings a digital revolution to the infrared visual inspection workflow. Anomalies detected by thermography can be recorded with precise positions on-site and viewed comprehensively on 3D models, eliminating the traditional issues of cumbersome recording work and positional ambiguity in one stroke. On-site recording tasks are greatly streamlined, and the resulting data are highly accurate and systematically organized. Because everyone can share the same digital data regardless of who performed the inspection, variability due to individuals is suppressed and reproducible inspections that do not rely on experience are achieved. Next, let’s look in detail at the specific effects of using LRTK.

Reliably Recording Anomaly Locations with Coordinates: Improving Re-inspection and Repair Instruction Accuracy

One major benefit of integrating infrared visual inspection with LRTK is that anomalies can be recorded with coordinates. Because latitude, longitude, and height information are attached to each anomaly point during the investigation, follow-up inspections and handovers to construction become markedly more accurate. This chapter explains how coordinate recording improves re-inspection and repair instructions.

First, simplified re-inspection. At the next scheduled inspection, you can call up the coordinate data of anomalies recorded previously with LRTK and re-check the exact same points. Using AR display, the previously marked locations appear as pins on the actual building, enabling pinpoint comparison and verification to see whether new deterioration has occurred or existing cracks have expanded. With paper records, differences in marking methods could make it hard to be confident whether it’s the same location, but coordinate data ensures tracking of long-term changes, aiding understanding of deterioration trends and preventive maintenance planning.

Next, improved accuracy of repair instructions. Conventionally, reports had to describe repair locations vaguely, such as “the third tile up to the right when viewed from the window of unit XX,” which forced repair crews to search on-site and introduced risk of mix-ups. With LRTK, every anomaly is stored as a unique coordinate data point. For example, you can specify “detached tile at north exterior wall at X = 12.3 m (40.4 ft)・Y = 5.2 m (17.1 ft)・Z = 18.7 m (61.4 ft),” enabling repair personnel to locate the exact point without confusion. In a case where LRTK was used for tile detachment inspections on a ten-story building, crews reported that they could reach the target tile simply by following the AR guide on the smartphone screen without repeatedly checking drawings on the scaffold. Visual guidance based on coordinates helps prevent location mix-ups and missed repairs.

Furthermore, coordinate data are useful for repair planning. Knowing the positional coordinates of each anomaly makes it possible to analyze trends such as “many anomalies concentrated on the south face” or “deterioration distributed around height ○m.” This allows you to accurately narrow the areas where scaffolding needs to be installed or prioritize repair areas. On the LRTK cloud, viewing a list or map of anomaly points enables automatic aggregation of repair quantities (how many tiles need replacement, how many meters of crack need repair, etc.) at the push of a button. Quantity assessments that previously required manual extraction from reports and entry into spreadsheets are automated, leading to greater accuracy and speed in cost estimation and ordering.

In this way, visualizing anomaly locations as coordinates seamlessly links the inspection-to-repair process and bridges information gaps between the field, the office, and contractors. Reducing the need for re-inspections and visits and providing accurate repair instructions help restore building safety promptly, so accurate information transmission through coordinate recording offers substantial value.

Visualizing Reports with Point Clouds and AR — DX Effects Driven by Digitalization

The 3D point cloud data and AR marking information obtained using LRTK do more than just serve as records; they transform the reporting process itself. Traditional reports typically consisted of plan views and numerous photos indicating deterioration, but LRTK adoption accelerates visualization and datafication of report contents. This chapter examines the efficiency improvements in report creation using point cloud data and AR, and the DX (digital transformation) effects they bring.

First, intuitive information sharing via 3D models. The point cloud model of the entire building scanned with LRTK holds very high value as a three-dimensional record of deterioration. Information that was difficult to convey with paper drawings and photos—such as “where on the building and how much deterioration exists”—becomes obvious if markers are displayed on the 3D model. All stakeholders can view the same 3D model via a browser, enabling three-dimensional sharing of the current condition including owners and facility managers. For example, by overlaying past data with current point cloud models you can perform quantitative time-series comparisons, such as checking how previously repaired areas have fared or whether north-side cracks have expanded compared to years ago. Strengthening traceability through digital archives enhances the persuasive power of explanations to building owners or management associations. Judgments that were previously intuitive about whether deterioration is advancing or not can now be presented visually and data-driven, facilitating smoother decision-making.

Next, improved efficiency in report creation. Because inspection data are digital, the labor-intensive tasks of report compilation are greatly simplified. As noted earlier, photos taken with LRTK automatically include coordinate tags, so each photo itself shows which part of a crack it depicts. The burden of manually creating and matching photo catalogs and deterioration distribution maps for reports is reduced, and report reliability improves. Also, exporting the list of all anomaly points marked on the cloud 3D model instantly aggregates the number and extent of parts requiring repair. Tasks that previously required manual transcription to drawings or spreadsheets for quantity calculations are no longer necessary, enabling comprehensive and rapid report generation. On-site teams that have implemented LRTK report dramatic reductions in time spent creating photo albums and drawings, allowing them to allocate more time to analyzing diagnostic results and preparing explanations for clients; additionally, explanations using 3D models have markedly increased building managers’ understanding. This is not merely efficiency improvement but a DX effect that raises the added value of inspection work.

Thus, digital reports enabled by LRTK provide visual impact and data comprehensiveness that paper reports could not achieve. The Ministry of Land, Infrastructure, Transport and Tourism is promoting the advancement and digitization of infrastructure inspections, and the on-site adoption of point cloud data and AR technologies aligns perfectly with this trend. To share findings from infrared visual inspections more clearly and effectively with stakeholders, digitizing reporting is an important step.

On-site Implementation Cases and Obtained Effects — Speed-up, Fewer Re-visits, Reduced Human Error

So, what level of benefits can be expected when LRTK is actually introduced into infrared visual inspections? Below are use cases from the field illustrating concrete outcomes such as improved inspection speed and enhanced safety and accuracy.

Case 1: Efficiency improvement in large condominium exterior wall inspection One management company combined LRTK with an infrared survey of a condominium exterior approximately 30 m (98.4 ft) wide and 10 m (32.8 ft) high. Previously, after infrared photography it took more than half a day to mark anomalies on drawings and organize them, but after introducing LRTK the task was completed with about 15 minutes of on-site work plus automatic cloud organization. By scanning around the building with a smartphone in hand and immediately AR-marking and photographing observed thermal anomalies, the 3D model and anomaly list were available in the cloud as soon as the inspection finished. As a result, inspections that formerly required 3–4 people for a full day were reported to be completed by one person in about half a day, demonstrating a dramatic improvement in inspection efficiency. In sites managing multiple buildings, the number of buildings that can be inspected per day has increased, creating flexibility in personnel and scheduling.

Case 2: Reduced scaffolding high-place work and improved safety In another building, infrared thermography and LRTK were used together for inspecting tile detachment. First, suspicious tile detachment points were identified from the ground with infrared photography, and then only necessary spots were inspected up close using a boom lift and marked with LRTK. Traditionally, full scaffolding and manual tapping of the entire facade were required, but infrared + LRTK enabled minimizing the scope and time for scaffolding. The time staff spent working at height was greatly reduced, directly lowering risk and cost. Also, because AR markers indicate which areas have been inspected, inspectors reported being freed from the anxiety of high-place work wondering “how far have we checked?” Another safety benefit was avoiding unnecessary contact with fragile exterior materials that might be further damaged by manual probing.

Case 3: Reduction in re-visits and rework An infrastructure inspection firm implementing LRTK was able to drastically reduce additional re-visits by acquiring detailed data during the initial inspection. Previously, mistakes such as “mismatch between photos and drawings” or “missing dimensional data for specific spots” were often discovered during report preparation, necessitating a return to the site. With LRTK, photos embed location information and dimensions can be measured later from the point cloud, so everything needed is captured in a single visit. This cut travel and labor costs while enabling faster report submission and higher client satisfaction.

Case 4: Suppression of human error When relying on paper drawings and handwritten notes, mistakes such as “misnumbering” or “photo-file mismatches” occurred fairly often. After LRTK implementation, the recording process was automated, and such human errors plummeted. Even for complex buildings with many anomaly points, cloud-based organized and centralized data management reduced reporting omissions and double-counting. The system’s consistency—“the same result no matter who records it”—leveled up the organization’s overall service quality, which was a significant benefit.

As shown above, combining infrared visual inspection with LRTK greatly enhances inspection productivity while balancing safety and accuracy. Introducing DX tools into the field not only speeds up work, but also enables near-zero oversight inspections and highly reliable, data-backed reporting. Mastery of these digital technologies is becoming the new standard in building maintenance and management.

Conclusion: Accelerate On-site DX with LRTK, a New Partner for Infrared Inspection

Infrared visual inspection’s non-contact, efficient condition diagnosis is highly useful for maintaining buildings and infrastructure. LRTK has emerged as the partner that maximizes the power of infrared inspection, and as described in this article, combining the two can digitalize and transform the entire inspection process. Bringing precise positioning data and 3D technology-backed objectivity into a field that once relied on experience and intuition heralds an era in which anyone can safely and reliably perform inspections.

In particular, innovations such as coordinate-attached recording of anomalies and AR navigation allow inspection results to flow directly into next actions (repairs and re-inspections). Eliminating information transmission loss and enabling data-driven decision-making will provide greater confidence to architects, building managers, and maintenance personnel. In reporting, replacing photo ledgers and drawings with digital data dramatically improves operational efficiency and explanatory power.

Moreover, LRTK is expanding its role beyond complementing infrared inspection to serve as a simple surveying and daily inspection tool. Tasks that once required specialist contractors—such as taking measurements before minor equipment additions or recording points of concern during routine patrols—are increasingly handled by on-site staff themselves. With precise positioning and 3D recording available on a smartphone, LRTK is truly a “versatile surveying and inspection device anyone can use,” strongly supporting the digital transformation of construction and maintenance operations.

With aging social infrastructure and building stock, promoting DX in inspection work is an unavoidable challenge. The combination of infrared visual inspection and LRTK offers a solution that achieves both safety and efficiency and will likely be adopted across many sites going forward. Take this opportunity to incorporate cutting-edge digital technologies into your inspection workflows and achieve both high-quality maintenance and operational efficiency. On-site DX for building and infrastructure inspection is unquestionably moving to the next stage.