[FFmpeg-user] fftfilt

[Paul B Mahol]

On Thu, Oct 14, 2021 at 1:08 PM Michael Koch <astroelectronic at t-online.de>
wrote:

> Am 14.10.2021 um 13:01 schrieb Paul B Mahol:
> > On Thu, Oct 14, 2021 at 12:59 PM Michael Koch <
> astroelectronic at t-online.de>
> > wrote:
> >
> >> Am 14.10.2021 um 12:53 schrieb Paul B Mahol:
> >>> On Thu, Oct 14, 2021 at 12:29 PM Michael Koch <
> >> astroelectronic at t-online.de>
> >>> wrote:
> >>>
> >>>> Am 14.10.2021 um 12:07 schrieb Paul B Mahol:
> >>>>> Sorry but I'm not on windows, so I can not use your script.
> >>>> Then try the below (slightly improved) version. It would become much
> >>>> simpler with variables:
> >>>> ARRAY_H = pow(2,ceil(log(ceil(W*10/9))/log(2)))
> >>>> ARRAY_V = pow(2,ceil(log(ceil(H*10/9))/log(2)))
> >>>>
> >>>> The test image contains wavelengths from 4 to 8 (in the center) to 16
> >>>> pixels per linepair.
> >>>> The filter wavelength is independant of input size. You can change the
> >>>> size in the first command (but it must be 1:1 aspect ratio, otherwise
> >>>> hstack would fail)
> >>>>
> >>> Since when hstack fails because of different aspect ratio?
> >> Because I first make the left half of the test image, then transpose it
> >> and then hstack them together
> >>
> >> The fftfilt examples do of course work with any aspect ratio.
> >>
> > I think you do not understand what aspect ratio really means.
>
> width / height
>

Doesn't all this introduces aliasing if not using power of 2 width and
height square dimensions?


>
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