Matlab function for extraction of phase from interferogram

This is my built function for matlab used for extraction of phase from interferogram in interferometry. There are 2 mode for operation. Mode 1 is manual operation of mouse-selecting side peak (the peak containing phase information of the interferogram) in the frequency space for the interferogram. Mode 2 is automatic selection of side peak with given peak width for the interferogram of enough number of fringes. For minimizing noise, mode 1 is highly recommended.
How to use
Mode 1: phase_extraction(data,1)
Mode 2: phase_extraction(data,2,peak_width) or phase_extraction(data,2)
Function output: extracted phase in form of matrix (radian unit)
where data and peak_width are interferogram data (= imread(*.bmp) or imread(*.png)) and width of the side peak in frequency space, respectively. Smaller wide reduces noise but too much small value results in breaking of final phase shift profile as too much information is lost. Omitting peak_width in calling function make the function runs with default peak width of 30. (30*30 data points in square box around peak are selected)
Details description is given in HTML publication of the code.