To eliminate the threat posed by cracks in porcelain insulators to the stable operation of equipment

an enhanced imaging method for crack defect detection based on active infrared thermography is proposed. However

the low emissivity of porcelain insulator surfaces limits the effectiveness of active infrared thermography. To address this issue

this paper enhances defect imaging from two aspects: post-processing algorithms and surface coating treatments. For porcelain insulators without room temperature vulcanized (RTV) silicone rubber coating

analysis of surface cracks reveals that the surface glaze creates "hot spots" at the edges of the insulator skirts

resulting in suboptimal imaging of crack defects. By applying first-order differential processing

the characteristic imaging effectively eliminates the influence of non-defect anomalous temperature regions

thereby improving the imaging quality of crack defects. For porcelain insulators coated with RTV silicone rubber coating

the RTV silicone rubber coating increases surface emissivity and suppresses additive noise

significantly enhancing crack defect imaging. The results demonstrate that combining first-order differentiation and characteristic imaging in post-processing can markedly improve the imaging of crack defects in porcelain insulators using active infrared thermography. Furthermore

applying an RTV silicone rubber coating to the porcelain insulator surface further enhances defect visualization.