Fig. 1. Composition of measurement system

Fig. 2. Angular deviation of laser spot center

Fig. 3. Flow chart of automatic measurement

Fig. 4. Laser spot brightness under different exposure time

Fig. 5. Binary image

Fig. 6. Edge detection image

Fig. 7. Establishment of coordinate system

Fig. 8. Calculation results of circle fitting

Fig. 9. Experimental platform of pinhole runner

Fig. 10. Image before and after rotation

Fig. 11. Distribution of laser spot center

Fig. 12. X position deviation of laser spot center

Fig. 13. Y position deviation of laser spot center