On Fri, 10 Aug 2007 04:34:03 +0200, Graeme Gill <[EMAIL PROTECTED]>  

> Øyvind Kolås wrote:
>> More theoretically correct
>> resampling methods like a Sinc filter with an infinite neighbourhood
>> definitly is not something one would want in the view code.

I'm not sure what you mean by view code here. Preview?

Sinc filter with infinite window is clearly a theoretical abstraction that  
can never be implemented. That's why Lanczos derived his finite windows  
function (in around 1930 IIRC!).

> I suggest reading the article, rather than jumping to the
> conclusion that a Sinc filter is a recommended option.
> Of course if near enough is good enough, then a box
> filter will work acceptably.
> Graeme Gill.


Reading the article you refer to clearly shows the frequency response of  
all these options. The crudity of box and tent is an incentive to find a  
better option. Lanczos would seem to be one better option if it can be  
correctly implemented on reduction.

Why do you say anyone is jumping to conclusions? Lanczos (L3 would be  
likely to be used) gives best suppression of side lobes and more passband  
than gaussian the only other option without huge side lobes that give  
heavy artifacts.

As Øyvind Kolås pointed out this may be much more relevant for other  
operations such as rotation and scew.

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