Mercurial > hg > octave-image
changeset 368:1fa9ce890166
Allow for odd shifts (from Eugeniy Mikhailov)
| author | hauberg |
|---|---|
| date | Wed, 22 Apr 2009 19:10:33 +0000 |
| parents | adf5b6998ace |
| children | 7cfd8a5a581a |
| files | inst/imtranslate.m |
| diffstat | 1 files changed, 9 insertions(+), 4 deletions(-) [+] |
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--- a/inst/imtranslate.m +++ b/inst/imtranslate.m @@ -25,6 +25,7 @@ ## @end deftypefn ## Author: Jeff Orchard <jjo@cs.sfu.ca> +## bug fix: Eugeniy Mikhailov in 2009 (removing fftshift and ifftshift they do no good) function Y = imtranslate(X, a, b, bbox_in) @@ -54,13 +55,17 @@ [dimy, dimx] = size(X); - x = ifftshift(fft2(fftshift(X))); + x = fft2(X); px = exp(-2*pi*i*a*(0:dimx-1)/dimx); - py = exp(-2*pi*i*b*(0:dimy-1)/dimy)'; + py = exp(-2*pi*i*b*(0:dimy-1)/dimy)'; % actually to correspond to index notation 'b' should be + % replaced with '-b' + % but I do not want to brake previous version compatibility + % note: it also must be done in the cropping iand padding code P = py * px; y = x .* P; - Y = real( ifftshift(ifft2(fftshift(y))) ); - #Y = ifftshift(ifft2(fftshift(y))); + Y = real(ifft2(y)); % fft return complex number + % for integer shifts imaginary part is 0 + % so real takes care of transfer from complex number to real if ( strcmp(bbox, "crop")==1 ) Y = Y( ypad(1)+1:dimy-ypad(2) , xpad(1)+1:dimx-xpad(2));