Abstract Among the various diseases that inevitably occur on expressways, cracks are the most common and are significant indicators of highway pavement damage. Timely and accurate crack recognition is urgently required for highway maintenance. Highway pavement crack recognition depends mainly on human visual inspection and expressway maintenance vehicles. These approaches are very time-consuming, labor-intensive, and difficult to implement in civil engineering. Cost-effective fixed PTZ (pan/tilt/zoom)-camera based crack recognition was investigated in our previous work. However, for pavement cracks captured at long camera distances, the limited resolution of the PTZ-vision results in low-resolution crack images. In addition, the cracks are weak features, such that the crack pixels density and distribution are significantly affected by the background noise, making it difficult to recognize these cracks. Aiming at to solve these problems, a high-order kernel based modified bicubic interpolation is proposed to typically reveal and characterize discrete pixel variations, obtaining high-quality super-resolution crack images, and improving the recognition performance of cracks. Extensive experiments in relation to crack datasets captured by PTZ-cameras on G4/highways in China are conducted to verify the performance of the proposed method. Two measurement parameters Just Noticeable Blue (JNB) and Structural Similarity Index (SSIM) confirm the high-quality of the super-resolution crack images. Experimental comparisons demonstrate that super-resolution crack images based crack recognition achieves out-performance, such that the mAP, precision (P), recall (R), and F1-score are increased to $95.3\%, 97.3\%, 96.1\%$, and $97.4\%$, respectively. This method proves the feasibility of high-efficiency crack recognition using modified bicubic interpolation for fixed PTZ-vision based expressways maintenance engineering.
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