High Pass Filter in Frequency Domain

The high pass filter can be obtained from low pass filter in frequency domain by,

Apply the high pass filter to the “img03.jpg” and report what you get.

The code for Ideal High pass filter is given below where the values for D0 can be easily modified.

%% Ideal High Pass Filter

clc

clear all;

close all;

I = imread(‘img03.jpg’); %% Reading Input Image

[m,n]=size(I); %% finding size of image and stroing in m and n

D0 = 5;%% CHANGE the distance parameter and observe the result

[u,v]=dftuv(m,n);%%

d= sqrt(u.^2 + v.^2);%% Calculating the distance

Lfilt = double(d <= D0);%% Creating filter as defined

Hfilt = 1-Lfilt;%% Generating High pass filter from low pass filter

Hfilt_s = fftshift(Hfilt);%% Shitfing the DC componnet to centre

Iff = fft2(I);%% Fourier Transform of the image

Rf = Iff.*Hfilt; %Multiplying filter with the image both are in Fourier Domain

R = ifft2(Rf); % Inverse fourier transfrom of the above filtered image

figure

% Displaying the original image

subplot (2,2,2); imshow(I);title(‘Original Image’)

% Displaying the final result

subplot (2,2,4); imshow(R,[]);title(‘Resultant Image after Filtering’)

% Displaying the mesh plot of filter tranfer function

subplot (2,2,[1,3]); mesh(Hfilt_s);title(‘Filter Mesh Plot D0 = 5’)