Fig. 1. Three-dimensional model of infrared thermal imaging detection for polystyrene foam board. (a) Overall schematic of polystyrene foam board; (b) model meshing

Fig. 2. Defect detection system of infrared thermal imaging

Fig. 3. Field test results. (a) Material for field experiments; (b) infrared thermography

Fig. 4. Infrared thermograms of on-site detection at different time. (a) 8∶00; (b) 12∶00; (c) 16∶00

Fig. 5. Comparison of measured and calculated values at different thicknesses. (a) 0-mm thick crack; (b) 5-mm thick crack; (c) 10-mm thick crack

Fig. 6. Relationship between crack width and maximum temperature difference under different thickness

Fig. 7. Relationship between crack thickness and maximum temperature difference under different width

Fig. 8. Relationship between crack width and maximum temperature difference under different ambient temperature conditions. (a) 5-mm thick crack; (b) 10-mm thick crack; (c) 20-mm thick crack

Fig. 9. Relationship between crack thickness and maximum temperature difference under different ambient temperature conditions. (a) 20-mm wide crack; (b) 40-mm wide crack; (c) 60-mm wide crack