Fig. 1. Technical scheme diagram

Fig. 2. Flow chart of laser stripe image processing. (a) Original video frame image; (b) adjust and correct the video frame image; (c) image ROI; (d) laser stripe lines; (e) extract image R channels and grayscale; (f) median filtering and morphological closed operations; (g) image binarization; (h) skeleton extraction; (i) connected domain analysis; (j) connected domain ROI

Fig. 3. Process diagram for extracting key measurement points at both ends of the wheel flange. (a) Interpolated laser stripe centerline; (b) endpoints and multiple inflection points; (c) endpoints and effective inflection points

Fig. 4. Schematic of wheel swing. (a) Wheel swing to the left; (b) wheel swing to the right

Fig. 5. Schematic of D_c, D_l, and wheel measurement area. (a) D_c and D_l; (b) wheel measurement area

Fig. 6. Measurement error of wheel flange thickness, when D_c ≈ 65 cm/D_l ≈ 15 mm and wheel swing angle α=0° and α≠0°. (a) α= 0°; (b) α≠0°

Fig. 7. Measurement error of swing angle under different D_c and D_l conditions