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Re: Determing true resolution of an image? [message #29702 is a reply to message #29599]

Sat, 09 March 2002 02:16

Martin Downing
Messages: 136
Registered: September 1998

Senior Member

"Timm Weitkamp" <weitkamp@esrf.fr> wrote in message
news:2aa6be0a.0203080819.23972200@posting.google.com...
> chrisduckworth@hotmail.com (cnd) wrote in message
news:<3c8856d3.58341995@news.mem.bellsouth.net>...
>
>> [...]
>> It sounds like you want to do an MTF (modulation transfer function)
>> measurment. This is a some what common measurment. If I rember my DSP,
>> you need to scan the analog image at a rate of 2.15 times the analog
>> nyquest.
>> But, umm, this is probably the wrong news group for this stuff.
>
> Well, be that latter point as it may. Chris, do you have a good
> textbook or tutorial reference for this stuff at hand? I happen to be
> concerned with this kind of problem but find it hard to get hold of
> efficient learning material on DSP fundamentals such as sampling
> issues (that 2.15 is not really intuitive).

I dont think this is cross posting - IDL users appear to be asking more and
more - how do I solve this problem, rather than how do I implement this
algorithm/fix this code in IDL :)

Well "intuitively", you need at least two samples per wavelength, one for
the peak and one for the trough, then you need a little extra to ensure you
do not get caught measuring the mid point each time. Of course - you can
produce some incomprehensible equations to the same effect!!

Martin

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[Message index]

		Determing true resolution of an image? By: wmconnolley on Tue, 05 March 2002 11:32
		Re: Determing true resolution of an image? By: chrisduckworth on Sun, 10 March 2002 20:21
		Re: Determing true resolution of an image? By: Martin Downing on Sat, 09 March 2002 02:16
		Re: Determing true resolution of an image? By: weitkamp on Fri, 08 March 2002 08:19

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