P3D Re: JPG and destruction

[boris@xxxxxxxxxxxx (Boris Starosta)]

My turn!

Ole's ad hominem attack on the Chinese aside, I can comment only on my
personal subjective experiences with JPEG, which have been both very good
(as far as image quality goes), and very bad (as far as getting others to
accept the high quality of such files).  People seem to be biased against
JPEG.

Part of the problem is that most people have seen only poor quality JPEG
compression (i.e. high compression ratios).  Perhaps this is Ole's problem
with the images on his site (http://hjem.get2net.dk/stereoskopklubben).
The images on my site, including anaglyphs, are also all JPEGs
(www.starosta.com/3dshowcase), saved generally as medium quality, medium
compression files.  When I save at high quality, which can still give a
compression ratio of close to 10:1, it impossible to detect JPEG artifacts
without significant enlargement of the image.

Looking again at Ole's anaglyphs, I wonder if maybe his source files were
JPEGs.  When making an anaglyph, it is important that the JPEG compression
step is done last, after compositing the pure uncompressed left and right
channels into an RGB image.  I have seen anaglyphs made with digital
cameras, where the original half-pairs are saved as JPEGs right in the
camera - such source images make for bad stereo pairs, because each half
pair image will contain different JPEG artifacts, and these produce retinal
rivalry when viewed in stereo.  Re-saving an anaglyph produced from such a
source, again as JPEG, only worsens the situation.

In reply to:


>From: Ole Hansen <oha@xxxxxxxxxx>
...
>John W Roberts - roberts@xxxxxxxxxxxxxxxxx - wrote:
...
>> Lossy compression affected the quality of 3-D image pairs less than
>> that of 2-D images of the same scene....
>
>So much for chineese science. Anyone wanting to see the destructive
>habits of JPG to stereograms (anaglyphs) are invited to visit:
>http://hjem.get2net.dk/stereoskopklubben
>
>The ghosting you see there on the JPG's is not present in the original
>PNG anaglyphs. Is there a browser where you can import PNG ?
>I will not use the stereovariant JPS if it can be avoided, because it
>has the same problem, allthough not so grave viewed with DepthCharge.


Respectfully submitted,



Boris Starosta

usa 804 979 3930

boris@xxxxxxxxxxxx
http://www.starosta.com
http://www.starosta.com/3dshowcase



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