CODEWITHSUNDEEP
fftmatlab
Usman YousafZai
Usman YousafZai

Reputation: 1120

Fourier Transform Filter

In the below image i have computed the Fourier Transform of an image. Now i want to apply ideal high pass filter on same image using DO=50.Code of Fourier Transform is mentioned with in Image.enter image description here

Upvotes: 0

Views: 1443

Answers (1)

Sohyun Ahn
Sohyun Ahn

Reputation: 250

I don't know what ideal high pass filter. So, I assumed that HPF is a circle-shaped filter. This is my code.

lena = im2double(rgb2gray(imread('lena.bmp')));
D0 = 50;
lpf = zeros(size(lena));
base_x = linspace(-size(lena,1)/2,size(lena,1)/2,size(lena,1));
base_y = linspace(-size(lena,2)/2,size(lena,2)/2,size(lena,2));
[x,y] = meshgrid(base_x, base_y);
lpf(x.^2+y.^2<D0^2) = 1;
hpf = 1-lpf;

LENA = fftshift(fft2(lena));
RESULT = LENA.*hpf;
result = abs(ifft2(RESULT));
figure, imshow(result,[])

First, I make HPF using 1-LPF. (LPF' shape is circle.) And pixel-wise multiply image by HPF. Finally, ifft IMAGE.

When you run the above code, you can obtain this result.

original image Original Image HPF image HPF Image result image Result Image

Upvotes: 1

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