Fig. 1. Schematic of signal acquisition for white-light interferometry

Fig. 2. Schematic of traditional FDA algorithm

Fig. 3. Schematic of phase difference for discrete sampling interference signal analysis

Fig. 4. Schematic of ESAA

Fig. 5. Simulation sample and interferograms. (a) Original surface; (b) surface with a tilted dautm; (c) interferograms

Fig. 6. Simulation results. (a)(b) Surface topography and residual error measured by traditional FDA method; (c)(d) surface topography and residual error measured by ESAA method

Fig. 7. Comparison of cross-section profiles. (a) Traditional FDA method; (b) ESAA method

Fig. 8. Experiment setup

Fig. 9. Interferograms. (a) Grating structure; (b) spherical structure

Fig. 10. Grating structure measurement results. (a)(b) Surface topography containing the same inclined datum, measured by traditional FDA method and ESAA method; (c) inclined datum extracted from Fig. (b); (d)(e) surface topography after removing inclined datum from Fig. (a) and (b), respectively; (f) residual error between Fig. (d) and (e)

Fig. 11. Cross-section profile for grating structure. (a) Cross-section profile measured by traditional FDA method; (b) cross-section profile measured by ESAA method; (c) cross-section profile of residual error; (d) cross-section profile measured by stylus profiler

Fig. 12. Spherical structure measurement results. (a) Traditional FDA method; (b) ESAA method; (c) residual error between Fig. (a) and (b); (d)-(f) cross-section profiles of Fig. (a)-(c) at 250th row, respectively

Fig. 13. Measurement results after wavelet denoising. (a) Grating structure surface topography; (b) spherical structure surface topography; (c) cross-section profile of grating structure; (d) cross-section profile of spherical structure

Table 1. Residual analysis for two simulation results

Table 2. Step height of grating structure

Table 3. Residual analysis for spherical structure