Spatial-Temporal Motion Field Analysis for Pixelwise Crack Detection on Concrete Surfaces

Crack development in concrete structures starts at the micro-crack stage and proceeds to the macro-crack stage due to repeated cyclic loading, like ongoing vehicles on bridges. Automatic detection of early stage cracks is required for both safety and economic reasons. We present an automatic crack detection method that scans a captured concrete area and provides a pixel-wise localization of both visible macro-cracks and early stage micro-cracks from video sequences. The key component in the proposed method is a spatial-temporal non-linear filtering on framewise dense 2D motion field combined with Conditional Random Fields based crack localization refinement. We evaluate our method against labeled ground truth data provided by an expert crack inspector. Experimental results show that our method can produce high accuracy automatic crack localization having F1 score improvement of 0.14-0.22 compared to conventional image based detectors. The proposed method is also shown to detect cracks at an earlier stage which enables early preventive measures for repair operations.