Integrating the Symmetry Image and Improved Sparse Representation for Railway Fastener Classification and Defect Recognition

Figure 5

Demonstration of the idea of the construction of symmetrical sample. The dotted lines indicate the mean distance between the three classes of fastener images and intact training fasteners. The original distance, the first symmetrical distance, and the second symmetrical distance, respectively, express the feature distance between original test fastener, the first symmetrical fastener, the second symmetrical fastener, and intact fastener.