LPF in frequency domain

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MANDA
MANDA on 3 Dec 2022
Answered: Gokul Nath S J on 6 Dec 2022
clc; close all; clear
img = imread('PUPPY.jpg');
low_mask=zeros(M,N);
low_mask(M/2 - M/8:M/2 + M/8,N/2 - N/8:N/2 + N/8)=1; % DC+-16 pix : Low
LPF_img = ;%
How to make lpf image in frequency domain using this code ?
please .................
I don't know ....

Answers (1)

Gokul Nath S J
Gokul Nath S J on 6 Dec 2022
Hi Manda,
I am assuming LPF to Low pass filtering in digital Image processing. Please find the following code as an extension. I have converted an rgb image to grayscale assuming that you are having a colour image. If not kindly skip this step.
clc; close all; clear;
img = imread(PUPPY.jpg);
imgGray = rgb2gray(img);
[M, N] = size(imgGray);
low_mask=zeros(size(imgGray));
low_mask(M/2 - M/8:M/2 + M/8,N/2 - N/8:N/2 + N/8)=1; % DC+-16 pix : Low
LPF_img = fft(imgGray) .* (low_mask);%
Filt_img = ifft(LPF_img);
imshow(abs(Filt_img),[]);
In the 7th line, I am doing a frequency domain multiplication (time domain convolution) between the images. Finally in line 8, I did an inverse Fourier transform to convert the image from frequency domain to the spatial one.
Hope this helps!

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