1IM_FOURFLT(3)              Library Functions Manual              IM_FOURFLT(3)
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NAME

6       im_freqflt - filters an image with a float filter mask in the frequency
7       domain
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SYNOPSIS

10       #include <vips/vips.h>
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12       int im_freqflt(in, filtermask, out)
13       IMAGE *in, *filtermask, *out;
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DESCRIPTION

16       im_freqflt() performs filtering in the frequency domain  of  the  input
17       image  held by the image descriptor in with a mask held by the descrip‐
18       tor filtermask and writes the result on the image descriptor out.
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20       Image sizes should be power of two and  less  or  equal  to  512.   All
21       images should be one channel square images.  Image filtermask is a non-
22       complex one channel image created by  im_create_fmask().   Input  image
23       can be any type.  If input is complex, in and filtermask are multiplied
24       using the function im_cmultim(3).
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26       If input is not complex then  it  is  transformed  into  the  frequency
27       domain  and  then  it is multiplied with the filtermask.  In the latter
28       case the result is inverse fourier transformed and clipped to the input
29       image format using the function im_clip2fmt(3).
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RETURN VALUE

32       The function returns 0 on success and -1 on error.
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BUGS

35       The function has not been fully tested.
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SEE ALSO

38       im_fwfft(3), im_invfft(3), im_create_fmask(3), im_cmultim(3).
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41       N. Dessipris
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AUTHOR

44       N. Dessipris - 10/05/1991
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48                                  10 May 1991                    IM_FOURFLT(3)
Impressum