Re: [photo-3d] Digest Number 219

[Olivier Cahen <o_cahen@xxxxxxxxxxxxxxxx>]

	Hello Bruce. I often met the problem, as the Editor of my Club's
Bulletin. I receive pictures to be printed in the Bulletin, these
pictures being paper prints, normally 4x6". They are not always aligned,
so I must trim them for a good alignment .
	I do not consider theoretical develpments such as vectors. I first
check which is the left and which the right, with a View-Magic viewer,
since they are not always conveniently marked.
 	Then I choose a significant mark, such as the edge of a roof or the
eye of a person, in the right part of the picture, and I measure the
distance from this point to the upper edge of the picture, on both
prints, left and right. Then I do the same for a significant mark in the
left part of the picture.
	Then I cut the upper and lower edges of both prints at the same
distance of both left and at the same distance of both right marks. Then
I find where to cut the left and right edges of the prints, by hiding
these edges with a paper while watching them with my View-Magic viewer.
	Let me add that if you want to see these "vectors", it is easy in
polarized projection, you remove your polarizing glasses.


> Message: 11
>    Date: Wed, 30 Aug 2000 06:28:48 -0700 (PDT)
>    From: Bruce Springsteen <bsspringsteen@xxxxxxxxx>
> Subject: Algorithm Wanted
> 
> A sidebar to the tutorial.
> In his quiz explanation, George wrote:
> 
> >You can think of the stereoscopic deviations
> >as vectors which, in a properly recorded and mounted stereo
> >pair, lie in the horizontal direction.  Stereo projection
> >or anaglyph pairs give you a nice opportunity to study the
> >orientation of these vetors.
> 
> I'm looking for the most efficient algorithm - a set of steps - for
> locating and aligning those vectors in an un-registered pair of images.
> In other words, solve the following problem:
> 
> You have two large prints, unmounted left and right images of a stereo
> pair, marked L and R.  There is no obvious indication in the pictures
> (like a horizon) as to where horizontal should be in the stereopair.  The
> edges of the prints are not reliable as a guide - say the prints are cut
> round or ragged.  What then is the most efficient way to discover the
> direction of deviations in the pair?  You may mark or damage the prints if
> necessary to discover the answer - we assume that new clean prints may be
> made, once the vectors are located.
> 
> I'm interested in purely geometric answers, as well as real-world
> practical ones.  I have no "right" solution to offer, just my own ideas.
> 
> Bruce