understanding of Fast Fourier Transform

I am also working on same project... can anyone please tell me whats going on in fft enhancement i am unable to understand the loop as well as why we are diving picture into 32 by 32 pixel...!!!

    function [final]=fftenhance(image,f)
      I = 255-double(image);
      [w,h] = size(I); %out = I;
      w1=floor(w/32)*32; h1=floor(h/32)*32;
      inner = zeros(w1,h1);
      for i=1:32:w1 
        for j=1:32:h1 
          a=i+31;
          b=j+31;
          F=fft2( I(i:a,j:b) );
          factor=abs(F).^f;
          block = abs(ifft2(F.*factor));
          larv=max(block(:));
          if larv==0
             larv=1;
          end;
          block= block./larv;
          inner(i:a,j:b) = block;
        end;
      end;
      %out(1:w1,1:h1)=inner*255; 
      final=inner*255;
      %d=max(out(:)); %Find max pixel value in C. 
      %c=min(out(:)); 
      %figure   
      %imshow(out,[c d]);