[Leica] Fungus now filters

[pdzwig at summaventures.com (Peter Dzwig)]

The point of anti-aliasing is to smooth out "the jaggies", the jagged edges 
in 
digitised images caused by finite resolution. In theory with a large enough 
number of pixels in a camera you should be able to ignore the effects 
because 
the human eye wouldn't be able to resolve them. The need for anti-aliasing 
is a 
result of the artifacts introduced by the availability of a finite number of 
pixels to display an image in. For a standard monitor this number is 1.25Mp 
and 
here anti-aliasing is necessary without doubt.

It MAY be - and I say may because I don't know for certain - that at 14 MP, 
up 
to certain "reasonable" magnifications the effects are either not noticeable 
or 
are swamped by other effects or are cancelled out by the effects of other 
algorithms, when the digital image is viewed or printed.

Peter Dzwig

Don Dory wrote:
> All,
> The Kodak Pro14 or whatever their full frame 14MP camera is rumored to
> not use an anti-aliasing filter.  Likewise the internet rumor is that
> the D70 does not use one.
> 
> At least with the D70 I believe software is used to take the artifacts
> away as my friends give really mixed reviews to the output of this
> camera.  Like all software, it does what it was written for so if the
> subject matter looks like moir? then it will be removed.
> 
> My own tests with the D70 would seem to confirm this theory.  Shots of
> static objects with edges look really good.  Shots of complicated
> leaves, petals, and other really fine detail look like Summar images
> wide open(exaggerating here to keep some Leica content).
> 
> I wish Austin was still on the list as I believe that some chip design
> of some large number of pixels at some pixel pitch could show few
> artifacts of detail that the human eye could see.  Really, an
> engineering problem using acuity tests for the human eye and physics to
> design a sensor that minimizes artifacts in that frequency range.
> 
> Don
> dorysrus@mindspring.com
> 
> -----Original Message-----
> From: lug-bounces+dorysrus=mindspring.com@leica-users.org
> [mailto:lug-bounces+dorysrus=mindspring.com@leica-users.org] On Behalf
> Of Adam Bridge
> Sent: Friday, July 02, 2004 1:37 AM
> To: Leica Users Group
> Subject: Re: [Leica] Fungus in camera
> 
> It seems very odd to me that Leica is trying to eliminate the
> anit-aliasing filter. I distinctly remember my digital signal
> processing courses that state that before you sample an analog signal
> you have to limit the bandwidth with a filter to at least half the
> sampling frequence (and that would be if you had a perfect low-pass
> filter, you have to go lower for real-world filters.) Moire patterns
> would be the result because artifacts would be generated by digital
> sampling. I had a real-world example of this where we were measuring
> ion-acoustic waves in very low-density argon plasmas and got results
> that were really exciting - until the experimentalist realized he
> hadn't built-in the low-pass filter. When the filter was installed the
> "exciting" results vanished and things approached theory. Oh darn. But
> that wasn't with optical systems and maybe someone who's won the
> galactic institude prize for extreme cleverness has figured out how to
> avoid the artifacts.
> 
> I sorta hope so....but I'm wary of free lunches.
> 
> Adam
> 
> On Thu, 01 Jul 2004 08:49:02 -0400, Dan C <bladman99@yahoo.ca> wrote:
> 
>>The other article concerns the digital back for the R8/R9.  They are
> 
> aiming
> 
>>for a December launch, but they seem to be having problems getting the
>>internal image processing software ready.  Leica isn't happy with it.
> 
> An
> 
>>"anti-aliasing" filter isn't be used, and they appear to be having
> 
> problems
> 
>>solving the resultand moir? patterns visible is some images.   But
> 
> they are
> 
>>also confident these problems will be solved.   No sample images yet.
>>
>>-dan c.
> 
> 
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