Best Way of mapping a 360 FOV to a 2d image

Best Way of mapping a 360 FOV to a 2d image

Post by g.. » Wed, 29 Mar 2000 04:00:00


What is the best way (that is a view that contains all the 'information'
as least distorted as possible, short of storing a number of rotation
frames) to map a 360 FOV to a 2d bit map?
I want to take 360 FOV's of some bounded irregular surfaces (imagine
sitting on the inside of a hollow heart or any other organicky object)
and generate heightfields from them that could be used for some sort of
analysis. Suggestions on the resolution I may be looking at (of course
depends on irregulaity, but guesses are cool) to get accurate maps,
would be appreciated.

Please let me know if I am being unclear.
TIA

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Best Way of mapping a 360 FOV to a 2d image

Post by Helmut Dersc » Wed, 29 Mar 2000 04:00:00



> What is the best way (that is a view that contains all the 'information'
> as least distorted as possible, short of storing a number of rotation
> frames) to map a 360 FOV to a 2d bit map?
> I want to take 360 FOV's of some bounded irregular surfaces (imagine
> sitting on the inside of a hollow heart or any other organicky object)
> and generate heightfields from them that could be used for some sort of
> analysis. Suggestions on the resolution I may be looking at (of course
> depends on irregulaity, but guesses are cool) to get accurate maps,
> would be appreciated.

Common projections for this type of spherical panoramas are
the equirectangular type (used on certain types of worldmaps)
or a cubic mapping (6 rectilinear images with 90 degrees FOV).
You can see many images of these types at my website.
There are also a links to interactive viewers for these and other
formats (eg my multiplatform free PTViewer) and software
to generate and remap such images (eg my free Panorama Tools).

Helmut Dersch

-------------------------------------
Spherical Panoramas, Macro Panoramas,
Free Panorama Software:
<http://www.fh-furtwangen.de/~dersch>

 
 
 

Best Way of mapping a 360 FOV to a 2d image

Post by Doug Gonc » Fri, 31 Mar 2000 04:00:00


Buckminster Fuller shows the continents of the world laid out onto the faces of
an icosahedron in one of his books. I have such a printed map. It can be laid
out flat or tabbed together to form the wacky looking globe.

I guess you'll need triangle rotation and drag and drop in any software to lay
out the full spherical view from inside a heart. CAD software can provide a
half spherical view. I've done that. There might be something to do it more
recently. I laid out an extreme perspective in Visi Cad years ago. Just set the
one number to 90 degrees, and the whole visual field of half a sphere is
computed and displayed. It's a little disorienting. Only the connections with
various parts are correct. All the scales get distorted.

Quote:>What is the best way

Only you can decide what's best.

Quote:>as least distorted as possible,

The problem is that without a definition of distortion, we won't agree on what
is the least. And in any case, best is always for some reason. There's no
objectivity in it.

More than one way to skin a cat. Got a knife? What kind?

Hyperbolic geometry maps infinite space to a mere circle on the plane. But
that's two dimensional...

Teri and I used to play Action Biker, a Commodore 64 game. The play area in
that game is infinite, but connected at top and bottom. You can go in any
direction you want forever, but it gets boring because the scenery repeats
after a screen width or two. It turns out such a play area is topologically a
toroid, not a sphere. Topology is the geometry of connectedness or something
like that. You probably already know that. But that's the first step. Look for
the singularities on a sphere. You can't comb a hairy orange neatly. There's
always a whorl somewhere on it.

The regular polyhedra are the tetrachedron, octahedron, cube, dodecahedron, and
icosahedron. In Greek, that just means 4, 8, 6, 12, or 20 faces. They can be
subdivided. The whorl won't go away.

I guess you could lay out an infinite pattern of triangles on the screen and
map the 4, 8, or 20 sided polygons to them. The 4 sided tetrahedron could map
to one triangle with three on its edges. By repeating from those edges, you
might make a map that would help people navigate the spherical data set.

XY pixels are a pain for this. The pixels on a CRT are usually in triangles.
There are ways to scan a CRT in triangles, but once again, like that whorl,
you've got a problem. The triangles become redundant, while the whorl is a
singularity. Both are unavoidable problems. Be innovative. Try things.

 Yours,

 Doug Goncz
 Experimental Machinist
 Replikon Research
 Seven Corners, VA 22044-0394

 What I'm into:

 Home Page (1999-11-24):
 http://members.aol.com/DGoncz

 
 
 

1. Best way to get video image to LW 360

This is a very basic question, but I am not sure of the best approach.

I would like to capture a single image from my video camera, and print it
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I have:

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Is there a newer version of VM and if so any difference?
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Since I need only a few images, I do not want to purchase any other
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I realize that the grey scale is not good on the LW 360, but it is
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