[mdlug] current mdlug logo

[LAP]

On Sat, 10 Dec 2022 17:10:51 -0500
"Carl T. Miller" <carl at carltm.com> wrote:

> 
> I searched all over trying to find a better image, but this is
> the best one I could find.  Tinkering didn't help.  I tried to
> "sharpen" in 50% without good results.
>

In the first place, one has to understand the type of distortion
that is present.

This image is not "blurred" in the sense of being out of focus
or having been subjected to low pass filtering (Gaussian blur).
As a consequence, ordinary sharpening methods will not work.

This image suffers from severe JPEG compression artifacts, especially
ringing artifacts.  This kind of image, a cartoon-like image, should
never have been rendered in JPEG format.  PNG is most appropriate
here.  I don't know the history of this image but it seems to have
been compressed or enlarged or both with a high JPEG compression ratio.

Because of the considerable loss of information in JPEG compression
the image is essentially beyond salvaging.  The best hope for minimal
restoration would be programs like these (all Linux):

mhttps://github.com/victorvde/jpeg2png
(needs patching -- see issue #7)

https://github.com/ilyakurdyukov/jpeg-quantsmooth

http://viric.name/soft/qjpegrest/

I've tried the first two programs with NO improvement even at
very high iterations.

However, even though I am certain that all of the above is true,
I am just a novice at digital image science.  There may be some
newfangled methods somewhere that could do the job, but magic
in the sense of a perfect restoration can never be possible.

If such a logo is ever re-done from scratch, don't use JPEG
format.  JPEG, or any similar format, is only effective on artwork
with continuous gradations. Use PNG or SVG.