Fig. 1. Laser scanning process of vision sensor system

Fig. 2. Seam measurement by optical triangulation with scanning light. (a) V-shaped groove butt joint; (b) butt joint with misalignment

Fig. 3. Comparison of deformation amount under different weld joints. (a) V-shaped groove; (b) with misalignment; (c) small gap less than 0.5 mm and without misalignment

Fig. 4. Original weld seam image captured by vision sensor and its local large map

Fig. 5. Comparison of results using different median filterings. (a)-(c) Results of traditional median filtering; (d)-(f) results of improved median filtering

Fig. 6. V-shaped groove diagram extracted by slope analysis

Fig. 7. Principle diagram of magnifying details method based on threshold

Fig. 8. Curves of intercept (a) without magnifying details and (b) with magnifying details

Fig. 9. Extracted results of narrow-gap feature points (a) without magnifying details and (b) with magnifying details

Fig. 10. Image process and feature extraction

Fig. 11. Experimental results and error curves under different thickness conditions. (a) Thickness is 2 mm; (b) thickness is 3 mm

Fig. 12. Microtopography of weld seam. (a) Symmetric distribution; (b) off center