Takes frame (or stack of frames organized in x-y-FrameIndex) as input and performs the autocorrelation in x-y employng the Fourier ranform apporach. The resulting autocorrelation frame is averaged out for each input frame of the stack. After autocorrelation maxima is found, I compute the radial averaging. On the radial average of the AC, I perform Guassian fit to extract sigma and from that the FWHM. Togheter with this software I also provide a couple of speckles realizations (in staks or single frame in the files "Frm_Stack_Trial.mat", and "Frm_Trial.mat") . This routine also needs the radial average function radial_avg2.m (included).
[Frm_stack] : the input is a 3-d or 2-d matrix containing the speckles in the format x,y,,frame-index.
[FWHM] : Full width at half maximum of the speckle size (obtained with Gaussian fitting)
[AC XX] : Profile of the autocorrelation of the speckle frame; "plot(XX,AC)" to visaulize it
[curve] : result of the fit.to visaulize it "hold on; plot(curve)"
See also https://mlphotonics.wordpress.com/