Re: [photo-3d] Re: Hyperstereo & Lenticular

["John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>]

For the best hyperstereo effect with lenticular images, it is desirable to
have a wider, but equal spacing between each of the lenses.

If only the outside pair of lenses are given an extended base, the
hyperstereo effect will only be observed when your viewing position is to
one side, such that you are looking at the images produced by only the
outside lens and the one adjacent to it on that particular side.  You would
not, for example, get a hyperstereo effect when viewing this lenticular
picture head on.

When looking at a lenticular picture, we are only seeing the images of one
pair of lenses at a time, because we only have two eyes regardless of how
many lenses the camera has.

The reason for multiple lenses is so that we can view the resulting print or
transparency over a wider angle before we encounter a flat or pseudo image.
The more image elements, the more we can move to one side before we
experience one of these shifts, usually interpreted as a "jump" in the
image, and the smoother the appearance.

Lenticular images can be made with only two images (as from a conventional
two-lensed stereo camera).  However, these are very difficult to view, as we
must look at the image straight on without moving our head even slightly.

Now, however, it is possible to "create" easily viewable lenticulars shot
with a two lens camera on the computer.  The stereo parallax of the two
original images is used to create similar parallaxes in additional pairs
through interpolation (or extrapolation, depending on the stereo base that
you are starting out with and the direction you want to go).

With the desirability of equal spacing for all of the lenses in mind,
several years ago I built a mirror box for shooting hyperstereos with a
Nimslo.

It consisted of six mirrors.

Two of these mirrors were placed at 45 degrees in front of the two inboard
lenses similar to an image splitter configuration.  These reflected images
to the inboard lenses from two other "midboard" mirrors placed in front of
the outboard lenses.

These midboard mirrors were actually double mirrors, in that the glass was
coated with a mirror coating on both sides.
Thus, they did two things.

First, they served as outboard mirrors for the center lenses, reflecting the
scene from the outboard lens position to the inboard lenses, thus doubling
the stereo base of the inboard lenses.

Second, they served as inboard mirrors for the outboard lenses, directing
the image from the outboard mirrors to the outboard lenses.

This leaves the outboard mirrors which directed their view of the scene to
the back side of the midboard mirrors.

Confused?  Read over the previous very carefully.

The result of all of this is that the stereo base (optical centerlines) of
all four lenses was doubled:  extended by exactly the same amount.

It should also be obvious that this same configuration could be extended for
any number of lenses (as long as the number was even: 6, 8, 10 lenses, etc.)
by adding that many more pairs of double-sided midboard mirrors to each of
the intermediate pairs of lenses.

JR


----- Original Message -----
From: "Bob Mannle" <3dguy@xxxxxxxxxx>
To: <photo-3d@xxxxxxxxxxx>
Sent: Saturday, October 21, 2000 4:52 PM
Subject: Re: [photo-3d] Re: Hyperstereo & Lenticular


> Yet another purpose for hyperstero...
>
> is in the production of lenticular 3D images.
>
> All 3D lenticular images I produce contain a series of images,
> usually somewhere between 12 - 24. Because the lenticular lens
> only allows you to see a portion of these images at one time
> it is necessary to use extreme hyper between the outside pair.
>
> It's not unusual to use 200-300% of a normal stereo base. This
> will vary depending upon the specific lenticular lens being
> used, and what it can deliver.
>
> Personally I love hyper images, especially for cityscapes, or
> views of the Grand Canyon... It's what the Jolly Green Giant
> sees with his eyes being 30 feet apart.
>
> Bob Mannle
> New Vision Technology / ProMagic
> http://www.3d-web.com
> http://www.promagic.com
>
>
>
>