Machine Learning and Thermography Applied to the Detection and Classification of Cracks in Buildings

Due to the environmental impacts caused by the construction industry, repurposing existing buildings and making them more energy-efficient has become a high-priority issue. However, a legitimate concern of land developers is associated with the buildings’ state of conservation. For that reason, infrared thermography has become a powerful tool to characterize these buildings’ state of conservation by detecting pathologies, such as cracks and humidity. Thermal cameras detect the radiation emitted by any material and translate it into temperature-color-coded images. Abnormal temperature changes may indicate the presence of pathologies, however, reading thermal images might not be quite simple. This research project aims to combine infrared thermography and machine learning (ML) to help stakeholders determine the viability of reusing existing buildings by identifying their pathologies and defects more efficiently and accurately. In this phase of the research project, it was used an image classification machine learning model of Convolutional Neural Networks (DCNN) to differentiate three levels of cracks in buildings. The model’s accuracy was compared between Multi-Spectral Dynamic (MSX) images, conventional and thermal images, all acquired from two distinct thermal cameras. Fused images (formed through multisource information) were also used, so the influence of the input data and network on the detection results were analyzed.