所以我有这个'我'的形象。我用F = fft2(I)得到2D傅里叶变换。为了重建它,我可以去ifft2(F)。
问题是,我需要仅从a)幅度和b)F的相位分量重建这个图像。我如何分离傅立叶变换的这两个分量,然后从每个变换重建图像?
我尝试了abs()和angle()函数来获得幅度和相位,但第一阶段将无法正确重建。
帮帮我?
所以我有这个'我'的形象。我用F = fft2(I)得到2D傅里叶变换。为了重建它,我可以去ifft2(F)。
问题是,我需要仅从a)幅度和b)F的相位分量重建这个图像。我如何分离傅立叶变换的这两个分量,然后从每个变换重建图像?
我尝试了abs()和angle()函数来获得幅度和相位,但第一阶段将无法正确重建。
帮帮我?
你需要一个矩阵大小相同的矩阵 F
和0相,和另一个相同的相 F
并且均匀的幅度。正如你所说 abs
给你量级。要获得均匀幅度相同的相位矩阵,您需要使用 angle
得到阶段,然后将阶段分成实部和虚部。
> F_Mag = abs(F); %# has same magnitude as F, 0 phase
> F_Phase = cos(angle(F)) + j*(sin(angle(F)); %# has magnitude 1, same phase as F
> I_Mag = ifft2(F_Mag);
> I_Phase = ifft2(F_Phase);
你需要一个矩阵大小相同的矩阵 F
和0相,和另一个相同的相 F
并且均匀的幅度。正如你所说 abs
给你量级。要获得均匀幅度相同的相位矩阵,您需要使用 angle
得到阶段,然后将阶段分成实部和虚部。
> F_Mag = abs(F); %# has same magnitude as F, 0 phase
> F_Phase = cos(angle(F)) + j*(sin(angle(F)); %# has magnitude 1, same phase as F
> I_Mag = ifft2(F_Mag);
> I_Phase = ifft2(F_Phase);
对这篇文章提出另一个答案为时已晚,但是......无论如何
@ zhilevan,您可以使用我用mtrw的答案编写的代码:
image = rgb2gray(imread('pillsetc.png'));
subplot(131),imshow(image),title('original image');
set(gcf, 'Position', get(0, 'ScreenSize')); % maximize the figure window
%:::::::::::::::::::::
F = fft2(double(image));
F_Mag = abs(F); % has the same magnitude as image, 0 phase
F_Phase = exp(1i*angle(F)); % has magnitude 1, same phase as image
% OR: F_Phase = cos(angle(F)) + 1i*(sin(angle(F)));
%:::::::::::::::::::::
% reconstruction
I_Mag = log(abs(ifft2(F_Mag*exp(i*0)))+1);
I_Phase = ifft2(F_Phase);
%:::::::::::::::::::::
% Calculate limits for plotting
% To display the images properly using imshow, the color range
% of the plot must the minimum and maximum values in the data.
I_Mag_min = min(min(abs(I_Mag)));
I_Mag_max = max(max(abs(I_Mag)));
I_Phase_min = min(min(abs(I_Phase)));
I_Phase_max = max(max(abs(I_Phase)));
%:::::::::::::::::::::
% Display reconstructed images
% because the magnitude and phase were switched, the image will be complex.
% This means that the magnitude of the image must be taken in order to
% produce a viewable 2-D image.
subplot(132),imshow(abs(I_Mag),[I_Mag_min I_Mag_max]), colormap gray
title('reconstructed image only by Magnitude');
subplot(133),imshow(abs(I_Phase),[I_Phase_min I_Phase_max]), colormap gray
title('reconstructed image only by Phase');