Fig. 1. System block diagram

Fig. 2. Flow chart of defect detection algorithm

Fig. 3. Preprocessing images.(a) Original hole image; (b) mean filtered image of hole; (c) gray close operation image of hole; (d) gray open operation image of hole; (e) original wire drawing; (f) close operation image of wire drawing; (g) original black thing; (h) close operation image of the black thing

Fig. 4. Images of difference image binarization. (a) Hole image; (b) wire drawing; (c) black thing

Fig. 5. Diagram of defect detection results. (a) Close operation of the hole image; (b) open operation of the hole image; (c) close operation of the wire drawing; (d) close operation of the black thing

Fig. 6. Structural factor characteristic diagram

Fig. 7. Feature maps. (a) Defects of small wire drawing; (b) defects of big wire drawing; (c) defects of hole; (d) defects of fold; (e) defects of the black thing

Fig. 8. Diagram of defect detection results

Table 1. Feature and defect classification matching table

Table 2. Test classification results