Fig. 1. Reference wave quasi common path method using dichroic mirrors^[27]. (a) Optical setup; (b) pinhole structure

Fig. 2. Optical setup of single reference beam method^[28]. (a) Controlling the spatial carrier through using a mirror; (b) using a mirror and a grating

Fig. 3. Simultaneous dual-wavelength parallel four-step phase-shifting interferometry^[49]. (a) Schematic of the method; (b) partial schematic of polarization array

Fig. 4. Simultaneous three-wavelength parallel phase-shifting interferometry using color camera^[56]

Fig. 5. Optical setup of three-wavelength self-reference interferometry using color camera^[59]