Fig. 1. Imaging of HUD system. (a) Imaging process; (b) HUD virtual image observed at different positions (1, 2, and 3 are the virtual images observed at the left, center, and right positions, respectively)

Fig. 2. Binocular measurement and binocular virtual image measurement of HUD. (a) Principle of binocular measurement; (b) binocular measurement for HUD virtual images

Fig. 3. HUD design model and simulation results. (a) Schematic diagram; (b) light trace diagram; (c) grid distortion; (d) spot diagram

Fig. 4. Virtual image coordinates simulated at different observation positions

Fig. 5. Track of virtual image center varying with observation position

Fig. 6. Simplified model of binocular measurement error caused by position change of image point

Fig. 7. Image point coordinate change and measurement error caused. (a) Change of image point; (b) measurement error

Fig. 8. Baseline systematic error and total measurement error caused by baseline change. (a) Baseline systematic error; (b) total measurement error caused by baseline change

Fig. 9. Experimental system for HUD virtual image measurement. (a) Schematic diagram of measurement system; (b) experimental setup; (c) actually projected image; (d) display virtual image [ camera is located at (-60 mm, 0 mm)]

Fig. 10. Virtual image shape measurement results. (a) Stereoscopic view; (b) side view

Fig. 11. Division of virtual image measurement results