clc

clear all

%Load image

I=imread('cameraman.tif');

I = double(I):

FI=fftshift(fft2(I));

[m,n]=size(I);

[X,Y]=meshgrid(1:n,1:m);

X=X-(n+1)/2;

Y=Y-(m+1)/2;

D=sqrt(X.^2+Y.^2);

imshow(I);

 

% --------------------Smoothing----------------------------------------------------------------

%---------------------Ideal LPF----------------------------------------------------------------

ILPF=D<60;

figure

J=ifft2(fftshift(FI.*ILPF));

imshow(abs(J),[]);title('Ideal LPF')

 

%-------------------Gaussian LPF--------------------------------------------------------------

D0=30;

GLPF=exp(-D.^2/(2*D0^2));

figure;

J=ifft2(fftshift(FI.*GLPF));

imshow(abs(J),[]);title('Gaussian LPF')

 

%-------------------Chebyshev LPF------------------------------------------------------------

cutoff=60;

n=1; %order 1

BLPF = 1 ./ (1.0 + (D./ cutoff).^(2*n));  

figure;

J=ifft2(fftshift(FI.*BLPF));

imshow(abs(J),[]);title('Butterworth LPF')

 

%------------------------------------------------------------------------------------------------

%-------------------Sharpening------------------------------------------------------------------ 

%-------------------Ideal HPF-------------------------------------------------------------------

IHPF=D>60;

figure

J=ifft2(fftshift(FI.*IHPF));

imshow(abs(J),[]);title('Ideal HPF')

 

%------------------Gaussian HPF----------------------------------------------------------------

D0=30;

GHPF=1-exp(-D.^2/(2*D0^2));

figure;

J=ifft2(fftshift(FI.*GHPF));

imshow(abs(J),[]);title('Gaussian HPF')

 

%-----------------Butterworth HPF--------------------------------------------------------------

cutoff=60;

n=1; %order 2

BHPF= 1 ./ (1.0 + (cutoff ./ D).^(2*n)); 

figure;

J=ifft2(fftshift(FI.*BHPF));

imshow(abs(J),[]);title('Butterworth HPF')