On Feb 4, 11:04 pm, Logan Kearsley <chronosur...@[EMAIL PROTECTED]
> wrote:
> On Feb 4, 9:49 am, IsaacKuo <mech...@[EMAIL PROTECTED]
> wrote:
[...]
> > Even assuming the iridescence eye works just fine, I don't
> > see how useful the information is. Knowing a light source
> > is along the surface of some cone doesn't seem as useful
> > as, say, knowing whether the light sources is vaguely to the
> > left or vaguely to the right. The latter information may not
> > be precise, but it's enough to crudely hunt down or avoid
> > the light source. With the information your sensor provides,
> > you can't even do that.
>
> You *can* do that. Any single point of color will give you a cone, but
> there will be an arc of constant color concave towards the light
> source with the colors varying differently on each side depending on
> whether the angle is increasing or decreasing. So, by combining
> information from lots of pixels across the whole eye, you can get
> directional information with resolution limited by the number of
> different colors you can distinguish.
>
> Thinking on it some more, though, I'm not entirely sure how one would
> deal with the superposition of multiple light sources muddying the
> pattern. I shall have to ponder this, but for now it seems like the
> best you could do is to make the eye fairly small, so you don't even
> try to get differential color information across a large surface, and
> average color information over the whole surface so that you can say,
> for example, lots of red means theres a light source somewhere on
> *this* cone, and lack of blue means there's an obstruction somewhere
> on *that* cone.
Addendum- if all else fails, one can narrow things down by simply
wiggling the eye back and forth in order to get fairly large changes
in angles, and see which directions the colors vary in. Or stretching
the eye over a bump or depression rather than a flat surface, to get
the same result without having to move.
> Multiple eyes spaced apart and facing in different directions could
> still give you multiple cones, though, so that you can deduce that a
> light source or obstruction must lie on the intersection of several
> cones. Hm. And I don't see why said 'multiple eyes' couldn't just be
> different regions of a single larger eye surface.... Aha! And that
> gets you to a single (or two, or maybe three- one on each side of the
> animal) large eye surface that can use color information to determine
> the angular position of light or shadow sources.
>
> -l.
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