Fig. 1. Schematic of white-light scanning interferometer

Fig. 2. Schematic of PCWD method. (a) Phase of ideal interference signal in wavenumber domain; (b) processing of interference signal with noise; (c) ideal linear fitting phase effected by different noise in wavenumber domain

Fig. 3. White-light interference signal in simulation

Fig. 4. Phase unwrapping and fitting results in wavenumber domain. (a) Phase in wavenumber domain; (b) phase after unwrapping; (c) linear component of phase; (d) nonlinear component of phase

Fig. 5. Histogram of z_s and z_p value distribution

Fig. 6. Statistical results of the influence of different noises on a₀ and a₁. (a) Diagram of proportion of Δa₀×Δa₁<0 and Δa₀×Δa₁>0; (b) histogram of |a0λA4π| in the condition of Δa₀×Δa₁<0 and Δa₀×Δa₁>0

Fig. 7. Surface profiles of mirror obtained by the value of z_s in three measurements. (a) M₁; (b) M₂; (c) M₃

Fig. 8. Morphology distribution along Y direction with X＝100 pixel in three measurements obtained by z_s

Fig. 9. Surface profiles of mirror obtained by the value of z_p in three measurements. (a) M₁; (b) M₂; (c) M₃

Fig. 10. Morphology distribution along Y direction with X＝100 pixel in three measurements obtained by z_p and local amplification result. (a) Region of Y is [0 pixel, 200 pixel]; (b) region of Y is [70 pixel，130 pixel]

Fig. 11. Distribution along Y direction with X＝100 pixel after the subtraction of results between M₁ and M₂