%function buterworthHighpass
close all;
clear all;
a=imread('201by201.jpg');
figure;
imshow(a);
title('Origin Image');
%图像傅里叶变换
[m n]=siza(a);
f_transform=fft2(a);
f_shift=fftshift(f_transform);
figure;
fftshow(f_shift,'log');
title('frequency Image');
%滤波定义
p=m/2;q=n/2;
d0=64;k=2;
filter=zeros(m,n);
for i=1:m %高通滤波器
for j=1:n
distance=sqrt((i-p)^2+(j-q)^2);
filter(i,j)=1.7*1/(1+(d0/distance)^(2*k))+0.5;
end
end
filter_apply=f_shift.*(filter);
image_orignal=ifftshift(filter_apply);
image_filter_apply=abs(ifft2(image_orignal));
image_filter_apply=imadjust(mat2gray(image_filter_apply));
figure;
imshow(image_filter_apply,[]);
title('Filtering enhanced Image');
figure;
fftshow(filter,'log');
title('Filter Image');
