%?an?aproach?of?getting?phase?principle?value?through?4?step?grating?shifting
function?[I0]?=?step4（imageFileAimageFileBimageFileCimageFileD）
%?imread?images
%?k?is?the?resize?weights
k?=?0.1;
A?=?sparse（double（imresize（rgb2gray（imread（imageFileA））k）））;
B?=?sparse（double（imresize（rgb2gray（imread（imageFileB））k）））;
C?=?sparse（double（imresize（rgb2gray（imread（imageFileC））k）））;
D?=?sparse（double（imresize（rgb2gray（imread（imageFileD））k）））;
%?save?phase_data?A?B?C?D;
%?load?phase_data?A?B?C?D;
%?main?step
[LW]?=?size（A）;
I?=?double（zeros（LW））;
for?i?=?1?:?L
??