How to convert this Ideal Band pass filter code to Band Reject filter

Here is my code:

% Ideal Bandpass Filter

clc

clear all

close all

ima=imread('Image1.tif'); ima = double(ima); figure(1); imshow(ima,[]); title('Original image'); imafft = fftshift(fft2(fftshift(ima)));

% Fourier Spectrum of Image

imafft2 = fft2(ima); imafft3 = fftshift(imafft2); s = size(ima); ma=max(max((imafft))); maxr = 0.5*sqrt(s(1)^2+s(2)^2); cutoff1 = maxr*30; cutoff2 = maxr*120; c=1; for i = 1 : s(1) for j = 1 : s(2) r = sqrt((i-1-s(1)/2)^2+(j-1-s(2)/2)^2); if( r < 30) z(i,j) = 0; else if( r > 120) z(i,j) = 0; else z(i,j) =511;

end

end

end

end

% Plots

imafft=imafft.*z/255;

ima_out = fftshift(ifft2(fftshift(imafft)));

ima_out =ima_out-ima; ima_out = 1-ima_out;

figure(2); imshow(ima_out,[]);

title('Filtered image (Ideal)');

figure(3); imshow(imafft3,[]);

title('Fourier Spectrum of Image')

imshow(z,[]);

title('Filtered');

Answer 1

[Yuvaraj Venkataswamy]

Please check the below FAQ link.

https://in.mathworks.com/matlabcentral/answers/82262-convert-band-pass-to-band-reject

[Dhruv Contractor]

Thanks a lot giving me some idea but this work butterworth and Gaussian but not for Ideal.