%Purpose:Reconstruct the object wave from the phase-shifting interferograms; %Input parameters:'I1','I2','I3','I4'Phase-shifting interferograms; %'ph1','ph2','ph3', phase shifts in 'I2','I3' and 'I4' with respect to'I1'; %Output parameters;Complex_Amp, complex amplitude of the reconstructed object wave; %'Amp_R','Amp_O', The amplitude of the%object and reference wave; function [Complex_Amp,Amp_R,Amp_O]=Four_Step_PSI_Reconstruction(I1,I2,I3,I4,ph1,ph2,ph3), Q1=I3-I1; Q2=I4-I2; Numerator=Q1.*(exp(j*ph3)-exp(j*ph1))-Q2.*(exp(j*ph2)-1); %Numerator of 'OR*'; Denominator=(exp(-j*ph2)-1)*(exp(j*ph3)-exp(j*ph1))-(exp(-j*ph3)-exp(-j*ph1))*(exp(j*ph2)-1); %Denominator of 'OR*'; Complex_Amp=Numerator./Denominator; %Reconstructed 'OR*'; a=I1-2*real(Complex_Amp)+2*abs(Complex_Amp); %(|O|+|R|)^2; b=I1-2*real(Complex_Amp)-2*abs(Complex_Amp); %(|O|-|R|)^2; Amp_R=( sqrt(abs(a))-sqrt(abs(b)) )/2; %Reconstructed Amplitude of Reference wave; Amp_O=( sqrt(abs(a))+sqrt(abs(b)) )/2; %Reconstructed Amplitude of Object wave; end %Reference: OPTICS LETTERS,34(22),3553-3555;