│Return to list│Previous page│Next page│

＜E-05＞：Mechanical Engineering

Large-Area Nondestructive Inspection Technology Using Infrared Active Thermography
― Nondestructive Inspection Contributing to the Maintenance of Large-Scale Structures ―

Research Overview

● Non-destructive testing using active infrared thermography: Challenges in implementing large-area inspections Active infrared thermography is an inspection method in which the surface temperature of an object is monitored using infrared thermography while the object is being heated by a heater or other heat source. By detecting anomalous temperature distributions in the acquired thermal images, this non-destructive testing technique can identify internal defects. It is expected to find applications in a wide range of fields, including civil engineering structures and metallic materials. On the other hand, because the inspection area depends on the heat-irradiated region of the heat source, inefficiency in inspecting large areas has been a practical challenge. ● Technical challenge: proposal of an inspection method for efficient and high-precision large-area inspection In our laboratory, to achieve efficient large-area inspection using this method, we propose and investigate an approach in which the heat source scans spatially while heating and observing the object (Fig. 1). Scanning the heat source enables continuous inspection over a large area. In addition, by performing the scan as a periodic back-and-forth motion, it becomes possible to convert the thermal images into phase images utilizing this temporal periodicity. It has been confirmed that abnormal features can be detected with higher accuracy in the resulting phase images than in the original thermal images (Fig. 2).

Potential Applications and Commercialization Prospects

● Development and social implementation of nondestructive inspection methods for maintenance of large-scale structures Conventional inspection and maintenance of large-scale structures generally rely on visual inspection and hammer sounding tests. However, issues have been pointed out regarding inspection efficiency, inspector-dependent variability in accuracy, and the need for scaffolding during inspection. The proposed method is a promising inspection technique that can overcome these challenges. It is expected to be applied to and deployed for a wide range of structures requiring periodic inspection, including building exterior walls, bridges, tunnels, and other large-scale civil infrastructure. 　 Fig. 1 Active thermographic inspection using periodic scanning heating on a building exterior wall (tile surface) Fig. 2 Thermal image obtained from the inspection shown in Fig. 1 (upper left) and the corresponding phase image after transformation (upper right); cracks behind the tiles can be detected in the phase image

Last updated date：October 15, 2026