Incidentally, for reciprocal odd integer scale factors, reduction
using an unexpanded kernel is just plain decimation and the kind of
interpolation kernel doesn't matter.
On May 1, 3:49=C2=A0pm, aruzinsky <aruzin...@[EMAIL PROTECTED]
> wrote:
> If you prefer this,
>
> http://www.general-cathexis.com/images/ORI_0.125X_LanczosUnExpandedKe...
>
> , to this,
>
> http://www.general-cathexis.com/images/ORI_0.125X_Lanczo***pandedKern...
>
> , then I suggest that you use an unexpanded interpolation kernel.
>
> Typically, commercial softwares expand the interpolation kernel for
> reductions because such expansion automatically provides
> antialiasing. =C2=A0SAR Image Processor gives the option of not
expanding
> the kernel. =C2=A0This is undesirable for natural images.
>
> On May 1, 9:24=C2=A0am, pg <pen...@[EMAIL PROTECTED]
> wrote:
>
>
>
> > On May 1, 8:12 am, hsyq...@[EMAIL PROTECTED]
wrote:
>
> > > Sorry for this late reply.
>
> > > 3 example online:
>
> > > A.www.PenangA1.com/png/1K.PNG
>
> > > B.www.PenangA1.com/png/4K.PNG
>
> > > C.www.PenangA2.com/png/ORI.PNG
>
> > Picture C should bewww.PenangA1.com/png/ORI.PNG
>
> > > The three examples above are fragments of a drawing that terragen
> > > produced just a few days ago.
>
> > > All three pictures were taken by the same screen capture program.
>
> > > If you take a look at Picture C (ori.png), it's from the original
> > > drawing ( resolution: 4096 X 3072 ), with file size of 37MB, in BMP
> > > format. In Picture C you can see patches of green leaves distinctly,
> > > arising from the brown wall.
>
> > > Picture B represents a screenshot fragment of the 37MB drawing as my
> > > desktop wallpaper (1024 X 768). As you can see from Picture B,
> > > although much smaller than Picture C, the patches of green leaves
are
> > > still separated from the brown wall.
>
> > > However, if you look at Picture A ... the patches of green leaves
> > > kinda melt into the brown wall behind it. Picture A was from a
> > > fragment of a 1024 X 768 picture (JPG format) that I shrunk from the
> > > original 37 MB BMP drawing. When I shrunk it, I use 100% JPG
quality,
> > > with the "Lanczos" option.
>
> > > The most im****tant thing is that comparing Picture A with Picture
> > > B ... as you can see, even if Picture A and Picture B were obtained
> > > from pictures with the same dimension ( 1024 X 768 ), albeit
different=
> > > pictures, the green leaf patches of Picture B can still be clearly
> > > seen, while Picture A, the green leaves and brown wall are all mixed
> > > up.
>
> > > Any comment ??
>
> > > aruzinsky wrote:
> > > > On Apr 29, 12:39=EF=BF=BDam, hsyq...@[EMAIL PROTECTED]
wrote:
> > > > > Hello !
>
> > > > > I do computer graphics as a hobby, and have produced quite a
numbe=
r of
> > > > > stunning graphics. Often time though, when I shrink the graphic
to=
put
> > > > > them online, they become blurred !!
>
> > > > > I do all kinds of computer graphics, from fractals to virtual
> > > > > landscape, to sci-fi rendering, using softwares ranging from
photo=
shop
> > > > > to terragen to povray.
>
> > > > > When I am satisfied with a certain creation, I often make a
master=
> > > > > copy with the resolution of 8192 X 6144 pixel. Why that size?
Beca=
use
> > > > > that's the largest size my puny computer (dual-core 3GHz CPU
runni=
ng
> > > > > XP with 4GB RAM) can produce within a reasonably timeframe.
(Give =
or
> > > > > take 8 hours for rendering).
>
> > > > > As the filesize for a JPG with 8192 X 6144 resolution may go up
to=
30+
> > > > > MB, I often have to shrink them to a more reasonable 1024 X 768,
> > > > > filesize about 800 KB or so.
>
> > > > > However, I found that when I do that, many interesting minute
deta=
ils
> > > > > that were in the 8K X 6K pictures (even when I shrink fit it to
my=
> > > > > 1024X768 desktop as wallpaper) are GONE. In the 1024 X 768 JPG
fil=
es,
> > > > > all those details become blurred. No matter it's a JPG ---> JPG
> > > > > shrink, or BMP ---> JPG shrink, or TIFF ---> JPG shrink, all
those=
> > > > > details are GONE !!
>
> > > > > I have experimented with many different graphic / photo
softwares =
in
> > > > > the shrinking process, all of them give me the same "blurring"
eff=
ect.
>
> > > > > Now my questions to all you Gurus as below ---
>
> > > > > 1. =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD
=EF=
=BF=BDCan you tell me of the best way to shrink a 8192X6144 size graphic
> > > > > to
> > > > > =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD
=EF=BF=
=BD =EF=BF=BD 1024X768 size graphic without losing the interesting
details?
>
> > > > > 2. =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD
=EF=
=BF=BDWhich software do you recommend to carry out the shrinking
> > > > > operation?
>
> > > > > Thank you all in advance !!!
>
> > > > > Sincerely,
> > > > > Lee
>
> > > > Instead of excess verbosity, you should post links to crops of
befor=
e
> > > > and after images showing the problem areas.
>
> > > > You (plural) are not entitled to ignore the adage, "A picture is
wor=
th
> > > > a thousand words."- Hide quoted text -
>
> > - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
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