How to shift from convolution product to the scalar product with arrays?

1 回表示 (過去 30 日間)
Rabih Sokhen
Rabih Sokhen 2022 年 2 月 8 日
hy guys, hope you are doing well
I know that the product of the 2 signals in the frequency domain is equal to the Fourier transform of their convolution in the time domain
Y(f)= x(f). h(f)= fft( conv( x(t), h(t))
However, I tried to do the same in 2d with array and I didn't get the same result, i expected that the plot in subplot(244) would be equal to the plot in subplot(247)
Any idea how to fix it ?
Thank you in advance
code:
clear all
clc
n=3;
m=5;
a=rand(n,m)
b=rand(n,m)+1i*rand(n,m);
c=conv2(a,b);
subplot(241)
pcolor(abs(a))
title('a')
subplot(242)
pcolor(abs(b))
title('b')
subplot(243)
pcolor(abs(c))
title('c=conv2(a,b)')
subplot(244)
pcolor(abs(fftshift(fft2(c,n,m))))
title('fft2(c)')
subplot(245)
tfa=fftshift(fft2(a))
pcolor(abs(tfa))
title('tfa')
subplot(246)
tfb=fftshift(fft2(b))
pcolor(abs(tfb))
title('tfb')
subplot(247)
tfab=tfa.*tfb;
pcolor(abs(tfab))
title('tfa.*tfb')

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