Fig. 1. Layout diagram of deformation monitoring system

Fig. 2. Flow chart of vertical deformation calculation method

Fig. 3. Light spot center image of near-infrared target

Fig. 4. Schematic diagram of camera image coordinates

Fig. 5. Schematic diagram of camera imaging geometry relationship

Fig. 6. Precision testing device. (a) Layout of monocular vision measurement system; (b) layout of altimeter and targets

Fig. 7. Accuracy test data curve

Fig. 8. A certain rail transit bridge

Fig. 9. Installation diagram of bridge deformation monitoring on site. (a) Monocular vision measurement system at bridge pier; (b) near-infrared target light at bridge mid span; (c) near-infrared target light at bridge pier

Fig. 10. Monitoring curve of bridge deformation on a certain day

Fig. 11. Monitoring data during the time period of 5:30‒6:30

Fig. 12. Monitoring data during the time period of 18:30‒19:30