Alias - in the context of signal processing refers to two different sets of
data which will have the same output if sampled too slow. When you try to
reconstruct the original data you can't tell which of the two original sets
it came from. When an image is made without an aliasing filter, two
different frequencies can get merged into one data value. When you
reconstruct the image you can't normally separate the two frequencies so you
would probably assume the lower frequency was the only desired one and you
would be wrong.
Reducing an image to fewer samples should not create artifacts. You would
just loose data - loose resolution.
Most file compression that is done automatically then reversed is lossless.
No information is lost. A common example is to encode a string of zeroes as
a number telling how many zeroes. No information is lost but no compression
will be achieved if the file being compressed is too random.
-jeff
> -----Original Message-----
> From: ScottGee1
>
>
> Hmmm . . . these (and almost all of my) prints were made by a
> commercial Noritsu digital printer on Fuji Crystal Archive paper.
>
> Since you mention Web display I'm now wondering how the
> compression that is applied to reduce file size for quick
> loading affects noise and clarity. Of course, that isn't the
> case in my example as I'm using full size files directly from
> the camera.
>
> My goal is to get past the tech talk and deal with what I (and my
> clients) can actually see.
>
> Thanks!/ScottGee1
>
> On 6/14/05, Winsor Crosby <wincros@xxxxxxxxxxx> wrote:
> >
> > Two thoughts.
> >
> > There is ink spread with even the best ink jet printer. It covers a
> > wealth of noise problems.
> > noise is more relevant because it is more visible,
> > especially on the sharper LCDs at least at 100 percent. I don't
> > understand why someone would get more noise in the reduced
> size for a
> > computer display since my experience and plenty of feedback from
> > others is that the noise gets less apparent in size reductions.
> > Maybe some anti-aliasing going on?
> >
> > Winsor
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