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

Figure 2

The four regions of interest in fastener image; (b) and (c), respectively, the first and second symmetrical fasteners generated from the original sample as shown in (a); we can see that the appearance of two new samples has a great change relative to original image; and the main difference lies in the fact that the intact fasteners and defective fasteners are the end region of the fastener.

(a) Original fastener

(b) The first symmetrical fastener

(c) The second symmetrical fastener