Re: this just in from NASA

[P3D jon siragusa <siragusa@xxxxxxxxx>]

At 11:08 AM 7/10/97 -0500, John W Roberts wrote:
>
>Speaking of making the images available to the public, I'm not sure I
properly
>understood one aspect of the .jps image format - part of the discussion on
>P3D seems to indicate that the file provides the stereo information and you
>can view it with whatever stereo technology you have handy, and part of the
>discussion seems to indicate that the file can be organized in a number of
>formats, each intended for use with a particular viewing technology. Could
>someone please explain this again?
>

A JPS can be arranged in a number of different formats.  A Descriptor 
that is embedded in the JPS lets applications know what the format is.

Now there are 2 situations when viewing a JPS file:

1)  You're viewing it with software that recognizes and utilizes 
    the Descriptor

2)  You're viewing it with software that is unaware of the Descriptor.


CASE 1:  Descriptor aware application

	The image will be shown how the application intends to
	show it.  For example, if you have viewer software that intended for
	anaglyph glasses, a JPS in this case would come up in anaglyph.  
	If you have viewer software that supports multiple stereo methods,
	you'll typically have a choice as to which way you'd like the image
 	presented.


CASE 2: Application that doesn't know about Descriptors

	The image will be displayed as a normal JPEG.  How that actually
	appears depends on the original format of the JPS.  For example, 
	if you load an Anaglyph JPS into, say PhotoShop, it will appear as a
 	normal anaglyph picture.  If you load a side-by-side JPS into 
	PhotoShop, it will appear as a side-by-side pair.  If you loaded a 
	Side-by-Side JPS into a stereo viewer that expects an Interleaved 
	image, you'd get a screwed up image... :)  In short, a JPS will appear
 	"normal" in these application ONLY if it happens to have the same 
	format as the application expects.


So if possible, you should use JPS files with software that supports
the Descriptor, otherwise your image may or may not appear as you'd
expect.


>
>If the .jps files can be used in multiple ways, perhaps that would be a good
>way for NASA to make the stereo images available online.
>

Yep!  We (VRex) are talking to NASA about providing JPS versions of their
images.  They may be directly available from the NASA site, or they may be
mirrored on 3DExpo (http://www.3dexpo.com).

jon


------------------------------