[Gimp-developer] Downscaling quality.

[Geert Jordaens]

g4 at catking.net wrote:
> On Wed, 08 Aug 2007 11:57:00 +0200, Geert Jordaens 
> <geert.jordaens at telenet.be> wrote:
>
>>
>> I did some reading on image pyramid's (googling) and there the blur
>> action is described as a low pass filter.
>> Factoring the blur out is not a problem.  I also have to look to the
>> non-uniform scaling as mentioned by Sven and odd size.
>> If those things get fixed would this be a viable solution?
>> Geert
>
>
> Well blurring is technically a low-pass filter but such a crude one 
> you would not want to look at it's frequency profile.
>
> It's a rather crude way of masking imperfections rather than applying 
> a correctly designed filter appropriate to the scaling being done.
>
> /gg
>
>
What would be a correctly designed filter for scaling down by factor 2?

Geert