P3D Spatial JPEG resolution

[Tom Deering <tmd@xxxxxxxxxxx>]

>>> JPEG retains the spatial resolution of the original image....
>>It certainly does not !

This reminds me of something I learned in Chinatown a few years ago.  I
asked a friend how to "say thank you in Chinese."  She laughed and told me
there was no such thing.  She could tell me how to say it in Cantonese, for
example. But there is no one "Chinese language."

There is no one single JPEG compression.  There is a standard set of rules,
with some optional parts.   The JPEG standard does not specify exactly how
the compressing or decompressing software will behave.  The programmer can
choose a fast-but-less-acurate algorithm, or a slower-but-more-accurate
algorithm.  This is true for compressing and decompressing.  There is a big
difference in JPEGing software.

For instance, there is an optional step that squeezes the color part of the
image horizontally, while leaving the luminance part alone.  Some JPEG
software does this, others do not.  There is no one single "JPEG".

Nonetheless, I believe one element is the key to ruined stereo JPEGs. At
the lower quality settings, square, regularly spaced artifacts appear.
Since these artifacts are superimposed in 2D, they really stand out in 3D.
At the highest quality settings, these artifacts are almost always
invisible, at any resolution.

I might offer to set up a demonstration at the New York Stereoscopic
Society's June meeting is there is any interest.

Tom



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