#3DS -> RDS
>>how they work…
They work because the left eye is looking at one image (rather a vertical strip
of it) and the right eye is looking at the adjacent image strip. The two
strips are created such that the alignment of the individual corresponding dots
(or pixels for a background image) makes a stereo pair and "tricks" the
eye/brain connection. The method itself is very clever, simple, and confusing
<g> – for one mathematical description, check out RDSGEO.TXT from lib 10 in GO
GRAPHDEV.
I've been playing with stereo images of and on for about 20 years now, mostly
using dual images with a crossed-eye viewing technique (a headache!) I've made
piles of these things by hand, drawing the interocular/object diagram to scale
from the top view, measuring the offsets in the virtual images planes, and
drawing the final two images by hand.
Kilobaud had an article a while back (in the late '70s <g>) that gave the
algorithm to create 3D lissajou (sp?) patterns (or any 3D line drawing) which
could be plotted and viewed in 3D. Autodesk Autoshade would also render stereo
pairs – that was good fun.
The biggest problem with all the dual-image stereograms is one of scale: you
need two separate images small enough for your eyes to converge into one. With
SIRDS you can make BIG images! More fun, too, because of the "magic" of a
picture emerging out of a noisy "nothing."
I talked to my math-maniac friend today – he thinks he might be able to improve
on the algorithm IF he had access to the actual 3D data rather than the simple
greyscale image. Sounds like a candidate for an IPAS routine!
J K J
THOT for the day: what would stereo images be like if we had three eyes (in a
triangle) instead of two?