lpfhpf.m

CLPF 理想低通滤波ICHPF 理想高通滤波 的实现用于图像的处理

% ICLPF 理想低通滤波
Flpf1=Iclpf(F,0.4);
Flpf2=Iclpf(F,0.2);
Flpf3=Iclpf(F,0.06);
f1l=ifft2(ifftshift(Flpf1));f1l=uint8(real(f1l));
f2l=ifft2(ifftshift(Flpf2));f1l=uint8(real(f1l));
f3l=ifft2(ifftshift(Flpf3));f1l=uint8(real(f1l));
figure(2)
subplot(321);imshow(log(abs(Flpf1)),[]);title('ICLPF (r=0.4)');
subplot(323);imshow(log(abs(Flpf2)),[]);title('ICLPF (r=0.2)');
subplot(325);imshow(log(abs(Flpf3)),[]);title('ICLPF (r=0.06)');
subplot(322);imshow(f1l,[]);
subplot(324);imshow(f2l,[]);
subplot(326);imshow(f3l,[]);

% ICHPF 理想高通滤波
Fhpf1=Ichpf(F,0.4);
Fhpf2=Ichpf(F,0.2);
Fhpf3=Ichpf(F,0.06);
f1h=ifft2(ifftshift(Fhpf1));f1h=uint8(real(f1h));
f2h=ifft2(ifftshift(Fhpf2));f2h=uint8(real(f2h));
f3h=ifft2(ifftshift(Fhpf3));f2h=uint8(real(f2h));
figure(3)
subplot(321);imshow(log(abs(Fhpf1)),[]);title('ICHPF (r=0.4)');
subplot(323);imshow(log(abs(Fhpf2)),[]);title('ICHPF (r=0.2)');
subplot(325);imshow(log(abs(Fhpf3)),[]);title('ICHPF (r=0.06)');
subplot(322);imshow(f1h,[]);
subplot(324);imshow(f2h,[]);
subplot(326);imshow(f3h,[]);


%理想低通与高通滤波子程序编程如下：
function F1=Iclpf(F,r)
%ICLPF(Ideal Circular LowPass Filter)
% F is the FFT2 of an image;
% r is the radius of the filter,r ranges from 0 to 1
% F1 is the output of the transformed spectrum 
[m,n]=size(F);
a=fix(m/2);
b=fix(n/2);
R=r*(m/2);
for i=1:m
    for j=1:n
        d1=sqrt((i-a)^2+(j-b)^2);
        if (d1<=R)
           F1(i,j)=F(i,j);
        else F1(i,j)=0;
        end
    end
end 

function F1=Ichpf(F,r)
%ICLPF(Ideal Circular HighPass Filter)
% F is the FFT2 of an image;
% r is the radius of the filter,r ranges from 0 to 1
% F1 is the output of the transformed spectrum 
[m,n]=size(F);
a=fix(m/2);
b=fix(n/2);
R=r*(m/2);
for i=1:m
    for j=1:n
        d1=sqrt((i-a)^2+(j-b)^2);
        if (d1>=R)
           F1(i,j)=F(i,j);
        else F1(i,j)=0;
        end
    end
end