Structural Health Monitoring using Structured Lights and Infrared Thermography

Abstract

Structural health monitoring (SHM) is a nondestructive data-driven process used to assess the conditions of structural systems using methods like acoustic emission, ultrasonic, thermal imaging etc. In recent years with advancement in computer vision, research into vision-based inspection methods using three dimensional (3D) optical imaging and point cloud data is a field of active research. Structured light technique is an active method in 3D optical imaging where patterns are projected on to the scene and the camera captures the distorted pattern caused by the scene. The method uses the pattern distortion information to recover the 3D geometry. Therefore, instead of relying on the scene optical properties, the structured light method uses a projector to project known structured patterns onto the scene and the correspondence is established using the captured projected pattern information. Infrared thermography ((IRT) technique is another widely used technique for contactless temperature measurement and stress analysis of materials based on thermo elastic effects. Furthermore, IRT can be used to estimate fatigue limit and fatigue life curve of structural materials. For both visible and thermal imaging pixels are the data acquisition points used for surface profiling. However, thermal cameras have lower resolutions in comparison to visible light due to larger sensor elements. To overcome the limitations of IRT and to better investigate temperature dependent structural deformations we propose the use of projective transformations to map thermal information on to 3D reconstructed surfaces using structural light technique.https://ecommons.udayton.edu/stander_posters/4054/thumbnail.jp