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Antwort: Re: Image interpolation and display

Posted by Joachim Wesner on May 04, 2007; 3:58pm
URL: http://imagej.273.s1.nabble.com/Image-interpolation-and-display-tp3699590p3699593.html

ImageJ Interest Group <[hidden email]> schrieb am 04.05.2007 12:34:26:

>
> I once wrote some code for downscaling to arbitrary sizes
> with bilinear interpolation and I found it quite difficult
> to do it correctly - it seems the guys at Sun have not gone
> into that business...
>

Maybe it´s only a questions of terms but is´nt any "interpolation"
inappropriate for "downscaling" to anything below, say, 50%?

IMHO what you would need to do is an appropriate lowpass-filtering
(smoothing) of the data? (Where you later might again use "interpolation"
to find the value at the downsampled pixel coordinate if it is "off grid")

Using only interpolation to solve the "off-grid" problem alone must lead
to aliasing just because of the "undersampling" of higher spatial
frequencies
in the original image.

Joachim



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