show fourier transformed image in different scale

hey, i have the following code which i apply to my image:

A=imread('C:\Users\Viviko\Desktop\173149_11', 'tif');
A2=fft2(A);
iptsetpref('ImshowAxesVisible','on')
imshow(log(abs(fftshift(A2))+1),[])

i want to change the scale in axes and instead of going from 0 to approximately 2700, i'd like 0 to be shown in the middle of the axes, and so i could have both negative and positive coordinates. can please somebody give me a hint?

http://tinypic.com/view.php?pic=2dlpv2r&s=8#.U2fRZPl_tps

[Star Strider]

Duplicate post to: http://www.mathworks.com/matlabcentral/answers/128366-show-fourier-transformed-image-in-log-scale

[maria]

sorry, my mistake. do you have any idea?

[Image Analyst]

I removed the flag since someone deleted her prior question.

Answer 1

[Image Analyst]

Try this:

imshow(img, 'xData', [-2700,2700], 'ydata', [-2700,2700]);
axis on;

[maria]

that worked but when i try to find the brightest point of the image, the coordinates of the pixel are given in terms of the native image, not with the new one.

[Image Analyst]

Right. It gives the row, rowOfMax, and column, columnOfMax. You need to come up with a spatial calibration to convert row 1 to -2700 and the last row to +2700.

[rows, columns, numberOfColorChannels] = size(img);
[rowOfMax, columnOfMax] = find(img == max(img(:)));
xMax = (2700*2) * ((columnOfMax-1)./rows) - 2700;
yMax = (2700*2) * ((rowOfMax-1)./rows) - 2700;

[maria]

still sth is not working well, when I try this:

f = zeros(30,40);
f(5,20)=1;
[rows, columns, numberOfColorChannels] = size(f);
[rowOfMax, columnOfMax] = find(f == max(f(:)));
xMax = (size(f,2)*2) * ((columnOfMax-1)./columns) - size(f,2)
yMax = (size(f,1)*2) * ((rowOfMax-1)./rows) - size(f,1)

instead of getting the point (0, -10) I get xMax=-2 and yMax=-22