An identification and quantification method for debonding of ceramic tiled façade based on infrared thermography

Current infrared-thermography-based methods for detecting debonding still have notable limitations in both data acquisition and analysis. Suitable acquisition times are strongly affected by environmental conditions and are often selected empirically, which may degrade data quality or even lead to detection failure. In addition, the non-uniform composition of ceramic-tiled façades reduces defect detectability. To address these issues, this study focuses on the influence of solar radiation and analyzes the effects of solar position and radiation intensity, proposes a neighborhood multi-thresholding method for quantitative debonding detection. Outdoor tiled specimens facing four orientations and containing artificial debonding defects were fabricated and tested. The proposed method suppressed background interference and enabled quantitative area estimation. The mean absolute relative error ranges from 10% to 18% for defects larger than 3 cm × 3 cm, while the error rise up to 43% when 3 cm × 3 cm defects with smaller air-gap thicknesses of 2 mm are involved. Finally, an in-situ inspection of a west-facing tiled façade demonstrated the practical feasibility of the proposed method.