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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;

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.

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