I1=imread('blood1.tif');        
figure,imshow(I1)
f=double(I1);
g=fft2(f);%傅里葉變換
g=fftshift(g);%轉(zhuǎn)換數(shù)據(jù)矩陣
[N1,N2]=size(g);
n=2;
d0=5;
n1=fix(N1/2);
n2=fix(N2/2);
for i=1:N1
   for j=1:N2
     d=sqrt((i-n1)^2+(j-n2)^2);
     if d==0
         h=0;
     else
          h=1/(1+(d0/d)^(2*n));
       end
      result(i,j)=h*g(i,j); 
    end
end
result =ifftshift(result);  
X2=ifft2(result);             
X3=uint8(real(X2));
figure,imshow(X3)