Re: DIRDS

[P3D Larry Berlin <lberlin@xxxxxxxxx>]

>Harold R. Baize, Ph.D inquires:
> It sounds like a wonderful idea to be able to copy 
>the same SIRDS in the left and right channels and project or view 
>them to produce a stereoscopic image. I will have to try that. 
>However, I'm sure that would produce lower resolution than a true 
>DIRDS, since each eye would also be viewing dots that contribute to the 
>image of the other half of the pair. 
>
>If anyone knows of an existing Intel/MS-DOS/Win program that can 
>generate DIRDSs I would be very grateful for the information.

Dr. T. was right. Any SIRDS is made up of a series of DIRDS placed edge to
edge. The fact that there are different terms for them is mainly technical
and can be confusing since they are functionally the same thing. You can
create DIRDS with any stereogram program. Simply locate the halves you want
and separate them. Due to the nature of stereograms, there wouldn't be any
resolution loss by one approach compared to the other. A DIRDS image is
simply a stereo pair image, which is why stereograms and stereo pairs are
very closely related. Use random dots for coarse resolution and use
photographs for high resolution images.

The stereogram patterns featured on my website are essentially DIRDS that
have been designed to be fully tileable by matching on all edges. Most of my
patterns are created completely by hand manipulation in PhotoStyler and
don't require or use a depth map. Such an approach would be difficult with
large images but with small stereograms of the repeating type, you are
already size limited by the constraints of average inter-ocular spacing in
addition to the differences of various computer monitors. Check out my pages
for a few ideas, if you like.

There is a Windows program called SIS Gen 1.5 by W. A Steer, that is easy to
use and might allow you to juggle the dimensions during construction so that
you end up with a DIRDS made with a depth map. The idea is to have only
enough information to provide the left and right image. This is dependent on
the size of your depthmap and of your tiling image. Alternatively just make
any desired stereogram and cut out the appropriate left and right image
portions.  I have two URL's for his website and I'm not sure which is most
recent. They are:

        http://www-server.bcc.ac.uk/~zcapl31/stereo.html

and 

        http://www.ucl.ac.uk/~zcapl31/stereo.html

Have fun,

Larry Berlin

Email: lberlin@xxxxxxxxx
http://www.sonic.net/~lberlin/


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