??? Undefined function or method 'fftshow' for input arguments of type 'double'.
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Error ??? Undefined function or method 'fftshow' for input arguments of type 'double'.
when trying to display the image
c=imread('cameraman.tif');
cf=fftshift(fft2(c));
fftshow(cf,'abs')
or fftshow(cf,'log');
both are showing the same error how to overcome this
0 Kommentare
Antworten (6)
Wayne King
am 22 Mai 2012
What is fftshow.m ? That is not a MathWorks' function or method. If you have downloaded this MATLAB program from somewhere and saved it in a folder, then make sure you add that folder to the MATLAB search path with addpath or use pathtool.
0 Kommentare
Walter Roberson
am 14 Jun. 2012
3 Kommentare
Steven Lord
am 23 Nov. 2021
The code to call ifft is just ifft(). You need to fill in the input arguments to ifft inside those parentheses.
If you're asking to see the source code that implements ifft we do not distribute the source code for it. If you really want to see it start here.
Kumar Vaibhav
am 11 Aug. 2016
The error is due to fftshow function, which is not inbuilt function of MATLAB. You can find fftshow function in the link given below:
2 Kommentare
yanqi liu
am 20 Feb. 2021
sir, may be use the follow code
clc; clear all; close all;
c=imread('cameraman.tif');
cf=fftshift(fft2(c));
figure;
fftshow(cf,'abs')
figure;
fftshow(cf,'log');
function fftshow(f,type)
% from:https://ww2.mathworks.cn/matlabcentral/fileexchange/30947-gaussian-bandpass-filter-for-image-processing
% Usage: FFTSHOW(F,TYPE)
%
% Displays the fft matrix F using imshow, where TYPE must be one of
% 'abs' or 'log'. If TYPE='abs', then then abs(f) is displayed; if
% TYPE='log' then log(1+abs(f)) is displayed. If TYPE is omitted, then
% 'log' is chosen as a default.
%
% Example:
% c=imread('cameraman.tif');
% cf=fftshift(fft2(c));
% fftshow(cf,'abs')
%
if nargin<2,
type='log';
end
if (type=='log')
fl = log(1+abs(f));
fm = max(fl(:));
imshow(im2uint8(fl/fm))
elseif (type=='abs')
fa=abs(f);
fm=max(fa(:));
imshow(fa/fm)
else
error('TYPE must be abs or log.');
end
end
2 Kommentare
Reham bun
am 20 Feb. 2021
Bearbeitet: Reham bun
am 20 Feb. 2021
Sorry, i want to implement Gaussian low pass filter for this image, I used this code (ifftshow) for the inverted fftshow but it didn't work with me because the file is not found.
Here's my code
a=imread('Fig0441(a).tif')
whos a
g=fspecial('gaussian',688,10);
max(g(:));
g1=mat2gray(g);
max(g1(:));
f=fftshift(fft2(a));
i=f.*g1;
fftshow(i)
f1=ifft2(i);
yanqi liu
am 20 Feb. 2021
sir, please copy to one m file, like follows
clc; clear all; close all;
a=imread('Fig0441(a).tif');
% whos a
g=fspecial('gaussian',688,10);
if ndims(a) > 2
a = rgb2gray(a);
end
if ~isequal(size(a), size(g))
a = imresize(a, size(g), 'bilinear');
end
max(g(:));
g1=mat2gray(g);
max(g1(:));
f=fftshift(fft2(a));
i=f.*g1;
fftshow(i)
f1=ifft2(i);
figure; imshow(f1, []);
function fftshow(f,type)
% from:https://ww2.mathworks.cn/matlabcentral/fileexchange/30947-gaussian-bandpass-filter-for-image-processing
% Usage: FFTSHOW(F,TYPE)
%
% Displays the fft matrix F using imshow, where TYPE must be one of
% 'abs' or 'log'. If TYPE='abs', then then abs(f) is displayed; if
% TYPE='log' then log(1+abs(f)) is displayed. If TYPE is omitted, then
% 'log' is chosen as a default.
%
% Example:
% c=imread('cameraman.tif');
% cf=fftshift(fft2(c));
% fftshow(cf,'abs')
%
if nargin<2,
type='log';
end
if (type=='log')
fl = log(1+abs(f));
fm = max(fl(:));
imshow(im2uint8(fl/fm))
elseif (type=='abs')
fa=abs(f);
fm=max(fa(:));
imshow(fa/fm)
else
error('TYPE must be abs or log.');
end
end
0 Kommentare
Raghunathan P
am 7 Apr. 2021
It is another library instead you can use this code:
c=imread('cameraman.tif');
cf=fftshift(fft2(c));
fl = log(1+abs(cf)); % Your DFT matrix of image 'cf' wil come HERE
fm = max(fl(:));
imshow(im2uint8(fl/fm))
or for advanced
function fftshow(f,type)
% Usage: FFTSHOW(F,TYPE)
%
% Displays the fft matrix F using imshow, where TYPE must be one of
% 'abs' or 'log'. If TYPE='abs', then then abs(f) is displayed; if
% TYPE='log' then log(1+abs(f)) is displayed. If TYPE is omitted, then
% 'log' is chosen as a default.
%
% Example:
% c=imread('cameraman.tif');
% cf=fftshift(fft2(c));
% fftshow(cf,'abs')
if nargin<2,
type='log';
end
if (type=='log')
fl = log(1+abs(f)); % Your matrix 'cf' wil come HERE instead of 'f'
fm = max(fl(:));
imshow(im2uint8(fl/fm))
elseif (type=='abs')
fa=abs(f);
fm=max(fa(:));
imshow(fa/fm)
else
error('TYPE must be abs or log.');
end;
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