Alt-BEAM Archive
Message #08460
To: beam@sgiblab.sgi.com
From: Bruce Robinson Bruce_Robinson@telus.net
Date: Sun, 19 Dec 1999 22:25:31 -0800
Subject: [alt-beam] Re: Lets Hypothesise...
Richard Caudle wrote:
>
>>
>> If any of this was true, then we would all have
>> one eye and one ear. The truth is that distance
>> is quite an important factor in navigating our
>> world. We have two eyes and two ears so we can
>> triangulate distances.
>
> Pish, Posh! The single eye/ear thing would work
> in a two dimensional world, but we happen to be
> in a three dimensional world. It's go nothing to
> do with triangulation. We have to percieve objects
> in a three dimensional space. The only time distance
> enters into the formula is when we are making a
> conscious effort to determine distance. Besides, I
> thought that triangulation took three points, not two.
>
> Prove me wrong.
Sorry, Richard. He's right -- almost. Our two ears primarily give us
direction. Experience (e.g. knowledge of thunder) and volume give us an
approximate idea of distance. Blind people do much better, using
relative volume, echoes, and vast experience.
Our eyes triangulate. Triangulation involves 3 measurements to define
the dimensions of a triangle. The measurements can be 3 points, 3
distances, 3 angles, or a combination thereof. In the case of vision,
it's two angles of the eyeballs, plus the distance between them.
And with vision, we are always judging distances unconsciously. It's how
I get the coffee in the cup first thing in the morning before my brain
is in gear. It's how people can drive a car over a familiar winding road
with no conscious awareness. And it's why my neighbour, with one
artificial eye, never pours liquids into a container that's sitting on
the counter -- he always puts his hand around the cup, glass, or
container.
And, by the way, most of the time, most of us live in a mainly
two-dimensional world. We don't turn our eyes up to the sky often
enough.
Bruce
8461 Sun, 19 Dec 1999 22:40:27 -0800 (PST) [alt-beam] Re: Lets Hypothesise... beam@sgiblab.sgi.com Darrell Johnson Ok, here's a little experiment to try:
Place an object on your desk.
Look at it.
Look away.
While looking away, reach out and grab it.
Gee, how did you accomplish that, if you don't measure
distances? (you were able to reach out and grab it
right?)
-darrell
--- Richard Caudle wrote:
> The way we navigate through our world is what I call
> the "Second star to the
> right, and straight on 'till morning" system. We
> pay little attention to
> distances and such things. We see something
> interesting, we go that way
> until we see it better. There's no real measurement
> involved. That's why
> we need maps and such things.
>
=====
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8462 Mon, 20 Dec 1999 17:46:18 +1100 [alt-beam] Re: Lets Hypothesise... beam@sgiblab.sgi.com Elmo Why bother.......
Well i think the ultimate goal of all Beamers should be to make
something that is not only cool but has a practical application as well.
Once you have the movement aspect of Beam Robotics under control, you
can move on to making use of this new found mobility by doing something
in your environment as you move around.
If you want two robots to interact and record information about their
environment you might want to know the exact distance between the two
robots so that each robots data can later be analysed and compared with
the data gathered by any other robot. For this you need to know the
exact distance and probably direction between each robot. Guess work or
rules of thumb are not good enough sometimes.
Sorry if i am sounding vage but i do have a few projects under way that
have these requirements and i am trying not to give up too much IP until
i have something working.
Trust me....knowing the exact distance between two robots in different
mediums can make the difference between a flock of robots that can move
around as a group and look cool, and a cluster of robots that can
perform scientific calculations and data gathering.
Elmo the practicalist (...is there such a word?)
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