Hi Thanks for reporting this.
fre, 17 04 2009 kl. 12:39 -0400, skrev Eugeniy Mikhailov: > suppose to shift/translate image but if (x_shift+y_shift) is odd > the resulting image get multiplied by -1. [snip] > === suggested fix: multiply the final result by (-1)^(shift_x+shift_y) This will only work when (shift_x+shift_y) is an integer. Does anybody have a better solution that also works for fractional shifts? > ============== 2nd bug ======================================== > Severe precision drop for small images: [snip] > Looks like problem is actually in the fft which used for translation, > since imtranslate algorithm > seems to be correct one. But I do not see an easy fix for second problem. I must admit that I don't really follow the algorithm, so I cannot really comment here. > It is a bit unclear to me why use fft is used for translation. Since > integer shift could be done in a simpler way, fractional shift is > another story. Yeah, I never really understood why anybody would use the Fourier transform in interpolation. It seems like a poor choice to use sine curves for interpolation, except in specialised situations. I think the 'imtranslate' function should be altered to except string that allows you to pick an interpolation method. Just like the rest of the interpolation functions in the package. Unfortunately, I don't have the time at the moment to work on this, so if anybody want to help out it would be much appreciated. Søren ------------------------------------------------------------------------------ Stay on top of everything new and different, both inside and around Java (TM) technology - register by April 22, and save $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco. 300 plus technical and hands-on sessions. Register today. Use priority code J9JMT32. http://p.sf.net/sfu/p _______________________________________________ Octave-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/octave-dev
