Fig. 1. Laser vision sensing system. (a) Mechanical structure of laser vision sensor; (b) working diagram of sensor

Fig. 2. Flow chart of laser vision sensor

Fig. 3. Different weld seams and corresponding laser stripe patterns. (a) (b) V weld seam; (c) (d) lap weld seam; (e) (f) butt weld seam; (g) (h) pipe weld seam

Fig. 4. Overall flow of the weld seam recognition algorithm

Fig. 5. Image median filter results under different templates. (a) 5 pixel×5 pixel; (b) 7 pixel×7 pixel; (c) 9 pixel×9 pixel; (d) 11 pixel×11 pixel

Fig. 6. Threshold segmentation results of different methods. (a) Gray histogram; (b) histogram bimodal threshold segmentation; (c) Otsu threshold segmentation

Fig. 7. Extraction results of laser stripe center line based on Hilditch thinning algorithm

Fig. 8. Flow chart of geometric center algorithm

Fig. 9. Extraction results of laser stripe center line by geometric center method

Fig. 10. Sketch of feature point extraction model

Fig. 11. System multi thread parallel diagram

Fig. 12. Flow chart of 3D reconstruction

Fig. 13. Solder joint imaging diagram

Fig. 14. Physical drawing of experimental platform. (a) Weld identification system; (b) work-piece to be welded

Fig. 15. Experimental process. (a) Welding image acquisition process; (b) collection process of actual position of solder joint

Fig. 16. Analysis of experimental results. (a) Recognition of weld feature points; (b)errors of X-axis, Y-axis, and Z-axis