Fig. 1. Schematic diagram of target surface normal measurement

Fig. 2. Polar coordinates of the normal line in target surface

Fig. 3. 3D structure of four apertures polarization 3D imager

Fig. 4. Transmission process of diffuse light inside an object

Fig. 5. Schematic diagram of light refracted from inside of the target to the air

Fig. 6. (a) Schematic diagram of polarization ellipse, (b) Schematic diagram of geometric relationship between normal line of object surface and polarization ellipse

Fig. 7. Variation curve of zenith angle θ with relative polarization direction

Fig. 8. Variation curve of azimuth φ with relative polarization direction

Fig. 9. Variation curve of normal vector error of 3D polarization inversion with relative polarization direction

Fig. 10. Calibration method of standard linear polarizer

Fig. 11. Calibration method of relative linear polarization angle of four apertures polarizer

Fig. 12. Physical diagram of calibration method of relative linear polarization angle of four apertures polarizer

Fig. 13. Calibration method of relative linear polarization angle of four apertures polarize (a) schematic diagram, (b)physical diagram

Fig. 14. Calibration result of relative linear polarization angle of four apertures polarizer (a) 532 nm laser, (b) 671 nm laser