Fig. 1. Two cylindrical coordinates with uncoincident axes

Fig. 2. Coordinate transformation relations in cylindrical coordinate systems

Fig. 3. Particle swarm optimization solution flow chart

Fig. 4. Experimental optical path of inclined illumination light measurement

Fig. 5. Experimental setup for measuring inclined illumination light

Fig. 6. Reconstruction results of specular and diffuse reflection. (a) Result of specular reflection on 1-FFT plane; (b) reconstruction of specular reflection image after filtering; (c) result of diffuse reflection on 1-FFT plane; (d) reconstruction of diffuse reflection image after filtering

Fig. 7. Flow of +1st-order image marking method on the 1-FFT reconstructed image plane

Fig. 8. Effect of gradual specular reflection weakening. (a) Strong specular reflection; (b) weakened specular reflection; (c) simultaneous existence; (d) diffuse reflection

Fig. 9. One object with a height difference of 9 mm, combined by two gauge blocks

Fig. 10. Height of measuring block by inclined illumination method. (a) Digital hologram; (b) 1-FFT reconstruction image; (c) FIMG4FFT reconstruction image; (d) phase difference image; (e) image with linear tilt terms removed; (f) image after denoising

Fig. 11. Contour image of the box in Fig. 10(f)

Fig. 12. Curve corresponding to the line in Fig. 10(f)

Fig. 13. Stud contour measured by inclined light illumination method. (a) Digital hologram; (b) 1-FFT reconstruction image; (c) FIMG4FFT reconstruction image; (d) phase difference image; (e) image with linear tilt terms removed; (f) image after denoising

Fig. 14. Three-dimensional phase distribution of studs at each viewing angle. (a) 0°; (b) 90°; (c) 180°; (d) 270°

Fig. 15. Three-dimensional topography after stud splicing