A new standard for infrared visual inspections: LRTK delivers geotagged images and precise repair instructions

Building exterior walls, rooftops, equipment piping, and solar panels are constantly exposed to rain, wind, and sunlight, so aging and deterioration are inevitable. If left unchecked, issues such as detached or cracked exterior tiles, damaged rooftop waterproofing layers, and missing insulation or corrosion on piping can affect not only appearance but also safety. In fact, there have been accidents in which portions of deteriorated exterior walls have fallen and struck passersby, so regular visual inspections (checks) are essential to prevent such serious incidents.

Traditionally, wall inspections have relied on visual confirmation by qualified personnel and full-surface sounding surveys using sounding rods or hammers. However, high-elevation work requires erecting scaffolding or using aerial work platforms, making inspections time-consuming and costly and posing safety risks to workers. Recently, one efficiency measure attracting attention for such wall surveys is the use of infrared visual inspection. This non-destructive testing method visualizes surface temperature distribution with infrared thermography cameras and detects internal detachment, moisture, and defects from temperature differences, enabling large areas to be examined in a short time. The Ministry of Land, Infrastructure, Transport and Tourism has officially recognized infrared camera diagnosis as an alternative to sounding surveys in revisions to the periodic reporting system, and infrared-based degradation diagnosis is spreading as a safe and low-cost survey method. Infrared cameras are used not only for building exterior walls but also to identify rooftop waterproofing failures, detect leaks in equipment piping, and inspect hotspots in solar panels.

However, the following challenges have been pointed out when conducting infrared visual inspections.

• Detected locations can be unclear: Thermographic images contain few surrounding landmarks, making it difficult to later determine exactly where on the building an anomaly occurred even if it appears in the image. This is especially true for large buildings or facilities with many similar locations—relying on images alone to find the problem spot in the field is not easy.

• Report creation is time-consuming: Organizing the deterioration points identified in infrared images into photo ledgers or onto drawings afterward requires significant effort. Manually marking anomalies on survey drawings or sorting and pasting photos by location makes report compilation cumbersome and prone to human error.

• Repair instructions can become ambiguous on site: When contractors carry out repair work based on reports, there are cases where they hesitate at the site about “which part exactly needs to be fixed.” Thermal images provide few positional clues, which can lead to missed repairs or miscommunication of instructions. Even if the defective part is identified, it is difficult to convey the exact location to repair personnel unless marks are made around it, leaving challenges in on-site communication.

One solution that resolves these issues and makes infrared visual inspections truly efficient and reliable is the use of LRTK, which combines the latest positioning technology with AR (augmented reality).

What is LRTK

LRTK is a compact, high-precision GNSS positioning device that attaches to a smartphone or tablet. With a single unit, it delivers centimeter-level RTK-GNSS positioning for accurate location identification, photo-based surveying using the smartphone’s camera and LiDAR for 3D point cloud scanning, and stable AR display without positional drift—realizing all the on-site measurement, recording, and instruction processes in an all-in-one solution. In addition, a dedicated app and cloud service let you save positioning data and captured photos and notes to the cloud on the spot and share them instantly within the team.

What used to require expensive equipment and specialized technicians—precision surveying and recording—can be completed quickly by a single field staff member with a smartphone using LRTK. Its ease of use and versatility have made it a new standard in exterior wall inspections. Combining infrared visual inspection with LRTK can simultaneously resolve the aforementioned issues of “unclear detection locations,” “burdensome report creation,” and “ambiguous repair instructions,” dramatically improving inspection accuracy and efficiency. Below, we look at the main functions of LRTK and the specific benefits each provides.

Accurately identify deterioration sites with centimeter-level GNSS (cm-level, half-inch-level)

With LRTK’s RTK-GNSS centimeter-level positioning, photos and notes taken during inspections are tied to precise location coordinates. Even when a thermographic camera detects an exterior wall anomaly, the coordinates of that spot can be recorded immediately, making it clear later “at which location the problem occurred.” You won’t have to worry about being unsure which part of a large building a pictured crack or tile detachment corresponds to. Traditionally, location identification relied on intuition and memory, but LRTK leaves accurate positional data backed by numbers, greatly enhancing the reliability of inspection results. Because location information is obtained in a global coordinate system, it is also easy to plot data on drawings or maps later to get an overall view.

Streamline report creation with geotagged images

Photos taken with LRTK automatically include positioning information (location coordinates and camera orientation), so you can immediately organize “which part of the building each photo shows” at a glance. The tedious manual tasks of comparing thermal and visible images and pasting them into a ledger are no longer necessary. Based on the acquired coordinate data, photos showing deterioration can be automatically mapped onto drawings or plotted on a 3D model, making the creation of deterioration distribution maps for reports smooth. Recorded information on cracks and detachments can be listed in the cloud, and the quantity and extent of areas needing repair can be calculated instantly. By eliminating the need to transcribe data into spreadsheets or perform manual quantity calculations, report preparation time is greatly reduced. Because photos are linked to locations, it is also easier to avoid location mix-ups or missing records on drawings, improving reporting accuracy.

Deliver precise repair instructions with AR display

LRTK’s AR function is a powerful tool for intuitively showing recorded deterioration points on site. When you view the building through a tablet’s screen, digital markings are overlaid in real time at the positions of pre-recorded cracks and detachments. 【For example, when you hold up the camera, virtual pins or markers appear on the wall, making it immediately clear which points require repair.】 Thanks to high-precision GNSS positioning, virtual objects align perfectly with the real world without the need to place markers or perform manual alignment as with conventional AR. This makes on-site instruction visual and precise, eliminating the confusion contractors may face about “which part to repair.” Even for unseen internal wall deterioration, opening at the position indicated by an AR pin will lead you directly to the problem area, helping prevent missed repairs. If inspection data stored in the cloud is shared before repair work begins, contractors can know the locations and quantities of deterioration before erecting scaffolding, enabling them to prepare necessary materials and plan work accurately. LRTK’s AR display makes repair instructions clear to everyone on site and contributes to smooth repair work without rework or communication errors.

Cloud integration for information sharing and long-term management

Inspection data acquired with LRTK can be synced directly to the cloud and shared in real time with the office away from the site. Immediately after the survey, stakeholders can review cloud-hosted 3D models and lists of deterioration points from office PCs and discuss repair priorities and methods in online meetings. Site conditions that were hard to convey in paper reports can be shared intuitively via 3D models and maps in the cloud, making explanations to owners and managers easier. Inspection histories accumulated in the cloud serve as a digital archive for long-term management and are useful for tracking aging and preventive maintenance. At the next periodic inspection, previously recorded deterioration points can be guided on site with AR, allowing pinpoint checks to see whether “the same spot shows new anomalies.” Moreover, by overlaying past point cloud models with newly acquired data, small deformations and crack progression can be quantitatively assessed. Strengthened data-based traceability allows evaluations such as “has a crack been expanding over the past X years?” to be made with evidence, increasing the persuasive power of explanations to building owners and management associations. In this way, cloud integration enables inspection data to be used long-term rather than ending as a single report, improving the overall quality of building maintenance PDCA cycles.

LRTK applications beyond exterior wall inspections

LRTK is useful not only for exterior inspections but also for a wide range of purposes such as simple surveying and 3D scan recording. Originally developed as a “smart surveying tool for all types of sites,” it is being used across many scenes beyond the construction field, including civil engineering and equipment management. For example, tasks traditionally outsourced to specialists—such as land boundary surveys, as-built data acquisition for earthworks, and indoor 3D measurements for renovation planning—can be handled in-house with LRTK. This can lead to greater operational efficiency and cost reductions. The high-precision point cloud scanning and AR recording techniques that proved effective in exterior inspections can also be applied to routine inspections of infrastructure structures like bridges and tunnels, deterioration checks of factory equipment and plant piping, and condition monitoring of solar panels and slopes. Visualizing site conditions digitally with LRTK promotes DX that connects the field and the office through data, achieving both safety and productivity.

By incorporating LRTK into infrared thermography inspections, previously unclear “locations of deterioration” and their “data” can be linked to enable accurate and efficient inspections. This approach, which overturns conventional wisdom through high-precision positioning records and digital technology, is becoming the new standard in building diagnostics and maintenance management. Its adoption will only grow, and a time will come when everyone routinely uses it. LRTK, accelerating on-site DX, is opening up the future of infrared visual inspections.