Re: Digital De-twisting?

[P3D Larry Berlin <lberlin@xxxxxxxxx>]

>Date: Thu, 02 Oct 1997 
>From: P3D Bill Davis writes:
>
>
>Will one of these new whiz-bang Stereo Software packages we've heard of
>lately allow one to easily remove rotational errors from single-camera
>stereo pairs? 
>..................  I know that I can manually do trial and error rotation in
>Photoshop and eventually remove the rotational errors, but that's _so_ many
>mouse clicks.  :--)

******  Rotational errors are still best repaired in PhotoShop or
equivalent. I've used PhotoStyler, PhotoShop and PhotoImpact. I presume that
PhotoPaint would work too.

>
>Do any of these programs offer an automatic recognition/matching kind of a
>thing that picks out homologous points or areas and squares them with each
>other before interlacing, anaglyphing or whatever?

*****  There is a program on the internet that takes stereo images as input
and creates a 3D model from the pictures. However, it has no automatic
recognition feature, unless it's been added recently. You have to
laboriously identify and peg corresponding points by hand. I'm hoping to
find or create an automatic recognition and alignment feature in some future
stereo software... Someone probably has something similar somewhere...

>.............
>Or do I just have to de-twist with Photoshop?  I'll have to be there anyway
>to remove some retinally-rivalling cars that had the audacity to move
>between my left and right exposures.
>
>Any help would be welcome, I am always happy to let others make things
>easier for me. :--)
>

The processes required to detwist an image are complex enough that it will
take a significant amount of programming to add them to the special stereo
editing tools. Look for it in future software somewhere down the line. There
are lots of things that are easiest in basic photo editing programs, so the
ideal set-up is your favorite photo software and a good stereo editing tool
(such as 3D Stereo Image Factory(tm)). Do the rotation fixes, clean retinal
rivalries, balance and improve focus/contrast etc. in a photo program then
save the results for finish work in 3DSIF. The special editing program is
ideal for taking the project to the next level which is adjusting the
vertical alignment, setting the window and final cropping or resizing. Once
the stereo aspects are set up, it's a snap to save as many different files
of as many different 3D styles as your heart desires. Working together the
programs become complementary to each other so you get the best results with
a minimum of fuss. If you've even done the entire process including the
stereo steps in regular photo programs you know it can be done but is quite
a bit more work.

You complain about the number of mouse clicks and I do that too. Usually
it's the reason I work 98% of the time in PhotoStyler instead of PhotoShop,
even though PhotoShop is undeniably more complex and up to date. There are
some things it won't do and many that are three times as hard to accomplish
by comparison. (more clicks and less natural and intuitive processes,
especially for stereo related adjustments)

Larry Berlin

Email: lberlin@xxxxxxxxx
http://www.sonic.net/~lberlin/
http://3dzine.simplenet.com/


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