CASA-Net: A Context-Aware Correlation Convolutional Network for Scale-Adaptive Crack Detection

Surface cracks in infrastructure are a key indicator of structural safety and degradation. Visual-based crack detection is a critical task for the enormous application demands of infrastructure industries. Convolution operations have been widely deployed due to the strong feature learning abilities. However, global feature dependencies of multi-scale cracks are ignored due to the limited receptive field.In addition, the detection of cracks with low contrast suffers a serious performance loss.Therefore, to address the scale-adaptive crack detection problem, we propose a context-aware correlation convolutional network for scale-adaptive crack detection named CASA-Net. CASA-Net is capable of extracting multi-scale crack features for distinguishing between cracks and surface backgrounds, and evaluating feature correlations to capture global contexts. CASA-Net is composed of the multi-scale distinguishing feature extraction (MDFE) module and the context-aware feature correlation (CAFC) module. Specifically, the MDFE module consists of multiple cascaded convolutional layers and distinguishing feature extraction layers (DFLayers). The CAFC module consists of a mapping block and cascaded correlators to capture the context-aware features for long-range interactions. The performance of CASA-Net is evaluated on a benchmark crack dataset. The experimental results indicate that CASA-Net outperforms rival methods by achieving an F1-Score of 0.65 and an AP50 of 63.9%.