[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
problems with imrotate 'fourier' method
From: |
Przemek Klosowski |
Subject: |
problems with imrotate 'fourier' method |
Date: |
Fri, 09 Sep 2011 12:19:14 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:6.0) Gecko/20110816 Thunderbird/6.0 |
I think there's a problems with imrotate()'s 'fourier' method;
it introduces a strange discontinuous shift. You can see it here:
a = zeros(7,7); a(3,3) = a(5,3) = a(5,4) = a(5,5) = 1;
imagesc(imrotate(a,128*eps,"fourier","crop",0))
imagesc(imrotate(a,129*eps,"fourier","crop",0))
If you change 'crop' to 'loose' you can see that for 128*eps the rotated
image is essentially unchanged, but for 129*eps it suddenly jumps to the
upper left corner.
Is it a problem with the rotate algorithm or with arithmetic in my
version of Octave? I used Octave 3.4.2 on Fedora 15, i686 platform.
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- problems with imrotate 'fourier' method,
Przemek Klosowski <=