Fig. 1. Production principle of dispersed fringe image

Fig. 2. Two-dimensional information extraction of dispersed fringe image by the MPP method

Fig. 3. Schematic of the calibration error for the central line position of dispersed fringe image

Fig. 4. Effect of piston phase error on the diffraction pattern of double rectangle hole. (a) Double beam interference factor without piston phase error; (b) double beam interference factor with piston phase error; (c) single rectangle hole diffraction factor without piston phase error; (d) single rectangle hole diffraction factor with piston phase error; (e) one-dimensional diffraction pattern of double rectangle hole without piston phase error; (f) one-dimensional diffraction pattern of double rectang

Fig. 5. Difference between the wavelength and the peak offset corresponding to the same peak position when the center line of the fringe is different

Fig. 6. Detection error before and after the improvement of the MPP method as the rotation angle calibration error increases

Fig. 7. Experimental optical path for the detection of piston error

Fig. 8. Dispersed fringe images corresponding to the two sets of piston error in the target wavelength range. (a) 0.055; (b) 100.055

Table 1. Detection results of the MPP method with different rotated angles when the piston error is -20 μm

Table 2. Accuracy of the MPP method before and after correctionμm