Fig. 1. Optical path scheme of differential motion grating displacement measurement system based on Moiré fringe projection imaging

Fig. 2. Light incidence normal to grating surface

Fig. 3. Schematic diagram of relationship between coordinate systems. (a) Coordinate system OXgYgZg; (b) relationship between coordinate systems OXdYdZd and OXgYgZg

Fig. 4. Schematic diagrams of relationship among system geometric error, pitch angle, and yaw angle. (a) Variation law of system geometric error with pitch angle and yaw angle; (b) variation law of system geometric error under combined effect of pitch angle and yaw angle

Fig. 5. Schematic diagram of relationship between maximum movement speed of measured grating and camera frame rate

Fig. 6. Simulation results of optical system. (a) Simulation result of optical system; (b) simulation spot image

Fig. 7. Simulation results of stacked grating stripes. (a) Simulated image of stacked grating stripes; (b) simulated images of stacked grating stripes after Fourier transform, filtering, and Fourier inverse transform

Fig. 8. Simulation demodulation results of stripe image displacement. (a)(d) Initial stripe images; (b)(e) interpolated grayscale value curves for each column; (c)(f) positioning results of stripe centerline