證明2D-FFT能夠拆分成兩個1D-FFT
阿新 • • 發佈:2019-02-14
經常可以在文獻上看到2D-FFT能夠以兩個1D-FFT來實現,今天我用MATLAB證明了,的確如此。MATLAB的程式碼如下
clear all; clc; f=ones(256,256); center_loc = size(f); rd = 2; f(round(center_loc(1)/2)-rd:round(center_loc(1)/2)+rd, round(center_loc(2)/2)-rd:round(center_loc(2)/2)+rd) = 0; figure(1);imshow(f); f2=fft2(f); f3=(abs(f2)); figure(2);imshow(f3); tmp=zeros(center_loc(1),center_loc(2)); %-the first 1D-FFT, for each row for i= 1:center_loc(1) tmp(i, :) = fft(f(i, :), center_loc(2)); end %-transpose the tmp, for column-based 1d-fft tmp = tmp'; %-the second 1d-fft, for each column for i= 1:center_loc(1) tmp(i, :) = fft(tmp(i, :), center_loc(2)); end tt = abs(tmp); figure(3); imshow(tt);
以下三張圖從上到下,分別對應程式碼中的figure(1~3)。
Figure(1):
figure(2):
figure(3):