Newsgroups: sci.image.processing
Path: cantaloupe.srv.cs.cmu.edu!europa.chnt.gtegsc.com!gatech!howland.reston.ans.net!Germany.EU.net!Munich.Germany.EU.net!eso.org!news
From: ndevilla@eso.org (Nicolas Devillard)
Subject: Re : Resolution
X-Nntp-Posting-Host: ns1
Message-ID: <1995Jun25.182656.377@eso.org>
Sender: news@eso.org
Reply-To: ndevilla@eso.org
Organization: ESO - European Southern Observatory, Garching by Munich
Date: Sun, 25 Jun 1995 18:26:56 GMT
Lines: 16

> Is there away to take an image, say from a frame grabber and zoom in
> without losing the resolution ?

Zooming in an image is not friendly for the signal. When you zoom pixels, an interpolation must take care about the creation of new pixels. No matter the algorithm you choose to interpolate, this will always be degrading the resolution.

At zoom factors of 1.4142 (sqrt(2), but some say 2.0) and above, the Shannon theorem proves your signal to be hardly distorted (of course, the simpler the signal, the less it is distorted).

If you only zoom in plain surfaces, the effects of interpolation won't be seen, whereas a complex picture will show interpolation errors, and very often aliasing effects.

Hope it answered your question,
N. Devillard





