fig1

Figure 1. Construction of a dataset containing images of 42CrMo steel billets. (A) Low-magnification microstructural image and sampling points at the cross-section of the cast billet; (B) Original sub-image at one sampling point; (C) 90° rotation of (B); (D) 180° rotation of (B); (E) 270° rotation of (B); (F) Mirror image of (B); (G) Mirror image of (C); (H) Mirror image of (D); (I) Mirror image of (E).