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Message no. 1
From: Mongoose <m0ng005e@*********.COM>
Subject: Re: Magnification systems
Date: Wed, 9 Dec 1998 13:19:36 -0600
:Well, please not forget one think mostly forgotten by those players that
:use them in munchkinious attempts (the vision mag.):
:One cybered dude needs to use his simple action to activate his
:cyberware. And as the "bad boys" are not all in the same ranges they
:have to swiftly switch their Range settings. This is a handycap, a small
:one, but a handycap. And I used it as a GM against those Munchies. They
:learned from this and now only use those vision mags if they realy need
:to hit that fellow over there badly.

It also takes a simple action to use a NON cyber device (BTW,
activating cyber is a FREE action). Does that mean that to shoot with a
scope (same effect as vis-mag) you need to use a simple, then another
simple to shoot? Realistic, maybe. How about if you are using a lazer
sight? That's also a device...
Obviously, some items (cyber or not) do not require extra effort to
use. Vision mag falls in this category. Why make it hard to use it
compared to other systems (like the smartlink itself, or any other vision
mod)?
If the user is getting TN's of 2, they (or their target) are
stationary. Movement on either or both sides (especially running) drives
the TN's up to less instantly fatal levels, as do other mods (cover,
light, wounds). If you get shot out in the open while standing still,
yeah, yer screwed. ( well, DUH :-) )

Mongoose
Message no. 2
From: Sean McCrohan <mccrohan@*****.OIT.GATECH.EDU>
Subject: Re: Magnification systems
Date: Wed, 9 Dec 1998 14:15:29 -0500
Quoting Mongoose (m0ng005e@*********.COM):
> It also takes a simple action to use a NON cyber device (BTW,
> activating cyber is a FREE action). Does that mean that to shoot with a
> scope (same effect as vis-mag) you need to use a simple, then another
> simple to shoot? Realistic, maybe. How about if you are using a lazer
> sight? That's also a device...

The laser-sight probably doesn't take an action, because they're
generally set up so that they automatically turn on when the trigger is
depressed a certain distance (or so I understand...). So, it wouldn't take
any extra effort. I'd probably require a simple action from anyone using
a scope (stopping to look through the thing), but also count that as an
'aim' action, giving them a +1. If they have to adjust the scope to a new
range (say, they change targets), that's another simple action, and DOESN'T
count as aiming. Of course, they may have developed auto-focus scopes,
especially if there's a rangefinder attached also.

--Sean

--
Sean McCrohan (mccrohan@**.gatech.edu) | "He uses his folly as a stalking
Grad Student, Human-Computer Interaction | horse, and under the presentation
Georgia Institute of Technology | of that he shoots his wit."
http://www.lcc.gatech.edu/~smccrohan | _As You Like It_, Act 5 Sc 4
Message no. 3
From: Mongoose <m0ng005e@*********.COM>
Subject: Re: Magnification systems
Date: Wed, 9 Dec 1998 14:26:59 -0600
: The laser-sight probably doesn't take an action, because they're
:generally set up so that they automatically turn on when the trigger is
:depressed a certain distance (or so I understand...).

Its a presure pad on the handle, usually, but yeah, same effect.


:Of course, they may have developed auto-focus scopes,
:especially if there's a rangefinder attached also.


Are you saying cyber-eyes are NOT auto-focus? That's gotta be clumsy...

Mongoose
Message no. 4
From: Bryan Covington <bryan.covington@****.COM>
Subject: Re: Magnification systems
Date: Wed, 9 Dec 1998 15:36:16 -0500
> Are you saying cyber-eyes are NOT auto-focus? That's gotta be clumsy...
>
I can just see the sammy sticking his pinky in his ear to
adjust the range on his vision mag.
Message no. 5
From: Jonathan P Martin <devotelyapathetic@****.COM>
Subject: Re: Magnification systems
Date: Wed, 9 Dec 1998 17:47:14 -0500
On Wed, 9 Dec 1998 14:15:29 -0500 Sean McCrohan
<mccrohan@*****.OIT.GATECH.EDU> writes:
>Quoting Mongoose (m0ng005e@*********.COM):
>> It also takes a simple action to use a NON cyber device (BTW,
>> activating cyber is a FREE action). Does that mean that to shoot
>with a
>> scope (same effect as vis-mag) you need to use a simple, then
>another
>> simple to shoot? Realistic, maybe. How about if you are using a
>lazer
>> sight? That's also a device...
>
> The laser-sight probably doesn't take an action, because
>they're
>generally set up so that they automatically turn on when the trigger
>is
>depressed a certain distance (or so I understand...). So, it wouldn't
>take
>any extra effort. I'd probably require a simple action from anyone
>using
>a scope (stopping to look through the thing), but also count that as
>an
>'aim' action, giving them a +1. If they have to adjust the scope to a
>new
>range (say, they change targets), that's another simple action, and
>DOESN'T
>count as aiming. Of course, they may have developed auto-focus scopes,
>especially if there's a rangefinder attached also.

Alright, how about this. Sam aims at goon number one who
is north of him at extreme range. Then he want to shoot goon number
two who is at long range due east of him. Assume he's using something
with a decent range, say an assualt rifle. Now how does the actions
break
down? Current rules it takes two that doesn't make sense to me. Try
rapidly changing your field of view with a pair of binoculars. So 4
under
your system. Not sure I like this. I'm thinking something like:
0 (Free action) Goes out to extreme range
1 (Simple action) Shoots.
2 (Simple Action) Find second guy
3 (Simple Action) Shoots.

The problem comes in the 3rd line. To find the other guy I'd
think he'd have to go back to no or minimal maginfication then refocus
out to him. That'd really be two actions which may be two much. Maybe
make 'snapping back' to normal range cost nothing? It'd make sense,
since a rapid return would be highly desirable if somebody engages
in melee or even short range firearms combat. Wouldn't slow down
Sam's alot, they could always attack 1 person at whatever range with
no mods an action but would make it so it's not always short range.
Hmm.....comments?

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Message no. 6
From: Mongoose <m0ng005e@*********.COM>
Subject: Re: Magnification systems
Date: Wed, 9 Dec 1998 17:27:49 -0600
: Alright, how about this. Sam aims at goon number one who
:is north of him at extreme range. Then he want to shoot goon number
:two who is at long range due east of him. Assume he's using something
:with a decent range, say an assualt rifle. Now how does the actions
:break
:down? Current rules it takes two that doesn't make sense to me. Try
:rapidly changing your field of view with a pair of binoculars.

I used to do something quite similar, actually; I filmed our schools
football games for training purposes. Our coach liked TIGHT close ups,
and I was the only camera man. I wasn't always far back from the field,
so I developed the ability to look through the viewfinder and my free eye
at the same time, using one to track the action and the other to frame the
shot. The camera was auto- focus, and I used the manual zoom (much
faster). If the thing had been a gunsight, I could have taken of thier
heads quite nicely... at almost any range. Of course, I was the only
assistant he had who could do this, but it seems a capabilty that could be
learned, or even built into the implant. Really, changing zoom does NOT
take time, and maintaining "area awareness" is easy if you have a
"PIP"
effect or something similar (though my concentration was intense enough
that I did ignore nearby events).
If you really want to limit this stuff, just say using any scope or
vismag requires use of a normal aiming action (with normal aiming benefit
and CP / movement restrictions). IMO, at long range, having a stable
aiming platform (like my camera tripod) is crucial for any use of
magnification, so "aiming" makes sense. Basically, this makes such things
an aiming accessory- which is, of course, just exactly what scopes are.

Mongoose
Message no. 7
From: Bryan Covington <bryan.covington@****.COM>
Subject: Re: Magnification systems
Date: Wed, 9 Dec 1998 18:15:41 -0500
> Alright, how about this. Sam aims at goon number one who
> is north of him at extreme range. Then he want to shoot goon number
> two who is at long range due east of him. Assume he's using something
> with a decent range, say an assualt rifle. Now how does the actions
> break
> down? Current rules it takes two that doesn't make sense to me. Try
> rapidly changing your field of view with a pair of binoculars. So 4
> under
> your system. Not sure I like this. I'm thinking something like:
> 0 (Free action) Goes out to extreme range
> 1 (Simple action) Shoots.
> 2 (Simple Action) Find second guy
> 3 (Simple Action) Shoots.
>
<snip>

The problem with all of this is that you are comparing
computerized servo controls with manual binoculars. This is completely
unrealistic. Currently we have cameras that can autofocus in about a second
(1/3 turn), as fast as someone with 3 actions per turn. Now consider that
eyes are smaller than camera lenses (less mass to move and inertia to fight)
and that it's been 62 years. I'm willing to rely on advances in the system
to compensate for this.
If you want to do this to mess with your players, great. But
I really don't see it as being grossly out of whack with the other things in
the world. (e.g. You can plug a computer into your nervous system and cruise
through ridiculously high speed datalines but they can't make a high speed
autofocus system? Please.)
Message no. 8
From: Fade <runefo@***.UIO.NO>
Subject: Re: Magnification systems
Date: Thu, 10 Dec 1998 11:18:41 +0000
> The problem with all of this is that you are comparing
> computerized servo controls with manual binoculars. This is completely
> unrealistic. Currently we have cameras that can autofocus in about a second
> (1/3 turn), as fast as someone with 3 actions per turn. Now consider that
> eyes are smaller than camera lenses (less mass to move and inertia to fight)
> and that it's been 62 years. I'm willing to rely on advances in the system
> to compensate for this.

I seem to recall that digital/electronic vision/magnification systems
do not use lenses and so does not requires focusing whatsoever.

I might well be mistaken, of course, but it seems reasonable.

Regards,
Fade
--
Fade

And the Prince of Lies said:
"To reign is worth ambition, though in Hell:
Better to reign in hell than to serve in heaven."
-John Milton, Paradise Lost
Message no. 9
From: Bruce <gyro@********.CO.ZA>
Subject: Re: Magnification systems
Date: Thu, 10 Dec 1998 12:54:18 +0200
-----Original Message-----
From: Fade <runefo@***.UIO.NO>
To: SHADOWRN@********.ITRIBE.NET <SHADOWRN@********.ITRIBE.NET>
Date: 10 December 1998 12:13
Subject: Re: Magnification systems


> The problem with all of this is that you are
comparing
> computerized servo controls with manual binoculars. This is
completely
> unrealistic. Currently we have cameras that can autofocus in about a
second
> (1/3 turn), as fast as someone with 3 actions per turn. Now consider
that
> eyes are smaller than camera lenses (less mass to move and inertia
to fight)
> and that it's been 62 years. I'm willing to rely on advances in the
system
> to compensate for this.

>I seem to recall that digital/electronic vision/magnification systems
>do not use lenses and so does not requires focusing whatsoever.

>I might well be mistaken, of course, but it seems reasonable.

How then is light gathered and focused onto the retina/imaging
surface?

-- BRUCE <gyro@********.co.za>
*Executive Engineer* *FrontLine Games*
Eva's Gyro
Message no. 10
From: Fade <runefo@***.UIO.NO>
Subject: Re: Magnification systems
Date: Thu, 10 Dec 1998 15:20:02 +0000
> >I seem to recall that digital/electronic vision/magnification systems
> >do not use lenses and so does not requires focusing whatsoever.
>
> >I might well be mistaken, of course, but it seems reasonable.
>
> How then is light gathered and focused onto the retina/imaging
> surface?

If optical magnification uses optics, what does electronic
magnification use?

Regards,
Fade
--
Fade

And the Prince of Lies said:
"To reign is worth ambition, though in Hell:
Better to reign in hell than to serve in heaven."
-John Milton, Paradise Lost
Message no. 11
From: Bruce <gyro@********.CO.ZA>
Subject: Re: Magnification systems
Date: Thu, 10 Dec 1998 16:28:02 +0200
-----Original Message-----
From: Fade <runefo@***.UIO.NO>
To: SHADOWRN@********.ITRIBE.NET <SHADOWRN@********.ITRIBE.NET>
Date: 10 December 1998 04:15
Subject: Re: Magnification systems


> >I seem to recall that digital/electronic vision/magnification
systems
> >do not use lenses and so does not requires focusing whatsoever.
>
> >I might well be mistaken, of course, but it seems reasonable.
>
> How then is light gathered and focused onto the retina/imaging
> surface?

If optical magnification uses optics, what does electronic
magnification use?

Light must be gathered by a lens... what happens to it after that
is dependent on the system. Electronic mag will no doubt map out
the incoming light into a grid form and zoom in on it.. thus the
graininess...

My best geuss anyway....

-- BRUCE <gyro@********.co.za>
*Executive Engineer* *FrontLine Games*
Eva's Gyro
Message no. 12
From: Bryan Covington <bryan.covington@****.COM>
Subject: Re: Magnification systems
Date: Thu, 10 Dec 1998 11:22:11 -0500
> > >I seem to recall that digital/electronic vision/magnification
> systems
> > >do not use lenses and so does not requires focusing whatsoever.
> >
> > >I might well be mistaken, of course, but it seems reasonable.
> >
> > How then is light gathered and focused onto the retina/imaging
> > surface?
>
> If optical magnification uses optics, what does electronic
> magnification use?
>
> Light must be gathered by a lens... what happens to it after that
> is dependent on the system. Electronic mag will no doubt map out
> the incoming light into a grid form and zoom in on it.. thus the
> graininess...
>
It's the same process by which PhotoShop zooms an image. The
method (in PhotoShop) is called "bicubic interpolation". Which basically
takes into account the pixels surrounding each pixel and makes extra pixels
with a gradation from one to the next.
For example: 3 pixels. Black, white black. Is zoomed 300% to
a 9 pixel line. You get a black pixel near each end and a fade from black to
white as you near the center with a white pixel in the middle.

This is all computer processing and is not anywhere near as
sharp as optical magnification. I imagine you could put electronic mag in a
natural eye by patching a processor into the optic nerve. It takes the info
from a given part of the retina and zooms it. You are still using lenses but
the natural ones in the eyes.

Which also brings up the issue of lenses again. I seriously
doubt that optical mag is using glass lenses like a camera is. Most likely
they are using a synthetic version of the natural lens (a gel filled lens
that is flexed to adjust the magnification). In this case think this way
it's most likely using the same muscles you have in you eye for focus (or in
a cybereye, the servos that replaced those muscles). Hold up your hand and
look at your finger, now shift your focus past your hand to a tree in the
yard. That's how fast the zoom is.
Message no. 13
From: Mongoose <m0ng005e@*********.COM>
Subject: Re: Magnification systems
Date: Thu, 10 Dec 1998 13:21:39 -0600
:>I seem to recall that digital/electronic vision/magnification systems
:>do not use lenses and so does not requires focusing whatsoever.
:
:>I might well be mistaken, of course, but it seems reasonable.
:
:How then is light gathered and focused onto the retina/imaging
:surface?


The same way as in any digital optical system. The optics are high
quality, and the resolution VERY high. To "Zoom" you simply crop the area
you need and enlarge it. If implemented as cyber, you would not even need
to "crop"- the mind could simply focus on the details of the zoomed area.
The description pretty clearly supports this method (by stating,
correctly, that zoomed images would be lower resolution than non-zoomed
ones).
Sheesh- that the EASY way to do it- why do folks expect cyberware to
function like Rube-Goldberg shit?

Mongoose
Message no. 14
From: Mongoose <m0ng005e@*********.COM>
Subject: Re: Magnification systems
Date: Thu, 10 Dec 1998 13:59:10 -0600
: Which also brings up the issue of lenses again. I
seriously
:doubt that optical mag is using glass lenses like a camera is. Most
likely
:they are using a synthetic version of the natural lens (a gel filled lens
:that is flexed to adjust the magnification). In this case think this way
:it's most likely using the same muscles you have in you eye for focus (or
in
:a cybereye, the servos that replaced those muscles). Hold up your hand
and
:look at your finger, now shift your focus past your hand to a tree in the
:yard. That's how fast the zoom is.

Faster in many cases- that's why sim-stars get cyber-eyes; depth of field
and speed of focus problems aren't so bad if its your own eyes, but would
get annoying looking through those of another.

Mongoose
Message no. 15
From: Adam Getchell <acgetchell@*******.EDU>
Subject: Re: Magnification systems
Date: Thu, 10 Dec 1998 15:43:43 -0800
>Light must be gathered by a lens... what happens to it after that
>is dependent on the system. Electronic mag will no doubt map out
>the incoming light into a grid form and zoom in on it.. thus the
>graininess...

Not true ... light can be gathered by a bolometer, a photomultiplier tube,
a fiber-optic array (which is not a classical lens), a flake of
gallium-arsenide, rhodopsin, etc. etc.

Small flat light gathering devices would probably be GaAs based.

> -- BRUCE <gyro@********.co.za>

--Adam

acgetchell@*******.edu
"Invincibility is in oneself, vulnerability in the opponent." --Sun Tzu
Message no. 16
From: Bruce <gyro@********.CO.ZA>
Subject: Re: Magnification systems
Date: Fri, 11 Dec 1998 08:58:54 +0200
-----Original Message-----
From: Adam Getchell <acgetchell@*******.EDU>
To: SHADOWRN@********.ITRIBE.NET <SHADOWRN@********.ITRIBE.NET>
Date: 11 December 1998 01:35
Subject: Re: Magnification systems


>>Light must be gathered by a lens... what happens to it after that
>>is dependent on the system. Electronic mag will no doubt map out
>>the incoming light into a grid form and zoom in on it.. thus the
>>graininess...
>
>Not true ... light can be gathered by a bolometer, a photomultiplier
tube,
>a fiber-optic array (which is not a classical lens), a flake of
>gallium-arsenide, rhodopsin, etc. etc.
>
>Small flat light gathering devices would probably be GaAs based.

So which of these technologies is most likely to be used in cybereyes?
Are any of them capable of rapid focus changes and the wear and tear
associated
with being on the front end of a shadowrunner?

Thanks

>--Adam

-- BRUCE <gyro@********.co.za>
*Executive Engineer* *FrontLine Games*
Eva's Gyro
Message no. 17
From: David Woods <david@*******.FREESERVE.CO.UK>
Subject: Re: Magnification systems
Date: Fri, 11 Dec 1998 19:25:50 +0000
Adam Getchell wrote:
>
> >Light must be gathered by a lens...

I assume from context you mean that light from a scene (i.e. outside
world) must be imaged by a lens?

You can actually use a pinhole as well. Modern automatic cameras have a
small aperture which means they have a large depth of focus. The smaller
the aperture, the larger the depth of focus and the pinhole is the
ultimate example of this.

Holographic Optical Elements can also acts as lens and mirrorlens arrays
can be used to form a superlens; but you are essentially correct.

> what happens to it after that
> >is dependent on the system. Electronic mag will no doubt map out
> >the incoming light into a grid form and zoom in on it.. thus the
> >graininess...
>
> Not true ... light can be gathered by a bolometer,

Surely this is just a detector? As I understood it, an image had to be
formed on an array of bolometers. All the thermal imaging cameras I've
seen use a lens to image the scene onto the array.

> a photomultiplier tube,

Again an image needs to be formed by a lens at the first stage.

> a fiber-optic array (which is not a classical lens),

An image needs to be formed on the plane of the array. The direction of
any family of rays entering a fibre will be be completely scrambled when
they exit.

You have to form an image on one end too get a image out of the other.

> a flake of
> gallium-arsenide, rhodopsin, etc. etc.

Explain?

> Small flat light gathering devices would probably be GaAs based.

How can you get an image out of these devices without a lens?

Regards

- David Woods
Message no. 18
From: Adam Getchell <acgetchell@*******.EDU>
Subject: Re: Magnification systems
Date: Fri, 11 Dec 1998 14:29:12 -0800
>Adam Getchell wrote:
>>
>> >Light must be gathered by a lens...
>
>I assume from context you mean that light from a scene (i.e. outside
>world) must be imaged by a lens?

Careful ... I didn't write the above.

>You can actually use a pinhole as well. Modern automatic cameras have a
>small aperture which means they have a large depth of focus. The smaller
>the aperture, the larger the depth of focus and the pinhole is the
>ultimate example of this.

Simple pinhole cameras can be used, yes. But not for anything sensitive.

>Holographic Optical Elements can also acts as lens and mirrorlens arrays
>can be used to form a superlens; but you are essentially correct.

What do you mean by this? A hologram is a very specific interference
pattern from a multisource laser. How are you forming optical elements from
this? Typically, a hologram recreates phase information from the original
two lasers given ambient light ...

>Surely this is just a detector? As I understood it, an image had to be
>formed on an array of bolometers. All the thermal imaging cameras I've
>seen use a lens to image the scene onto the array.

A bolometer is a resistor absorbing incident radiation with or without a
chopper. Applying a bias voltage allows measurement of the change in
resistivity, which is directly related to the incident radiation. Given a
grid of resistors you can have an imaging device. Hint: using chip
fabrication technology, we can make resistors very small.

>> a photomultiplier tube,
>
>Again an image needs to be formed by a lens at the first stage.

Not necessarily. A photomultiplier amplifies incident photons on a
detector. A lens will focus such, but when detecting faraway galaxies, the
transmissivity of the lens itself is a concern. Again, an array of fiber
optic light pipes (which are not lenses) of 99.999% transmissivity can
direct photons to a photomultiplier or CCD.

>> a fiber-optic array (which is not a classical lens),
>
>An image needs to be formed on the plane of the array. The direction of
>any family of rays entering a fibre will be be completely scrambled when
>they exit.

Incorrect. First, light pipes tend to preserve vector and phase information
-- that is their function -- by radially varying indices of reflection and
internal reflection. Second, if phase information is known -- deducible by
an interferometer or more simply, Fraunhofer lens, then the image vector
(tensor in the most general case of circular and/or linear polarization) of
the light can be transformed by the light pipe translation matrix to yield
final values. That is,

Ma = Pa

Where M is the translation matrix, a is the image vector, and P is the
sequence of eigenvectors. Given that M is going to be Hermitian for
real-world examples, you can always find eigenvectors, and hence,
eigenvalues.

>You have to form an image on one end too get a image out of the other.

See above.

>> a flake of
>> gallium-arsenide, rhodopsin, etc. etc.
>
>Explain?

Band gap properties of this material allow specific photons to be detected.
As the band gap can vary, the frequency detectible can as well.

>> Small flat light gathering devices would probably be GaAs based.

>How can you get an image out of these devices without a lens?

Briefly, you can directly convert the photon to a bias voltage, measure the
array of bias voltages, and reconstruct the image. Then use something like
bicubic interpolation or least-squares to calculate values in between, for
more resolution and/or anti-aliasing.

>Regards
>
>- David Woods

--Adam

acgetchell@*******.edu
"Invincibility is in oneself, vulnerability in the opponent." --Sun Tzu
Message no. 19
From: David Woods <david@*******.FREESERVE.CO.UK>
Subject: Re: Magnification systems
Date: Sat, 12 Dec 1998 03:05:15 +0000
Adam Getchell wrote:
>
> >Adam Getchell wrote:
> >>
> >> >Light must be gathered by a lens...
> >
> >I assume from context you mean that light from a scene (i.e. outside
> >world) must be imaged by a lens?
>
> Careful ... I didn't write the above.

It seems the only reasonable interpretation of the previous comment.

> >You can actually use a pinhole as well. Modern automatic cameras have a
> >small aperture which means they have a large depth of focus. The smaller
> >the aperture, the larger the depth of focus and the pinhole is the
> >ultimate example of this.
>
> Simple pinhole cameras can be used, yes. But not for anything sensitive.

It's depends how sensitive the detector array is. The real limit is the
resolution by diffraction, determined by the dimensions of the camera.

> >Holographic Optical Elements can also acts as lens and mirrorlens arrays
> >can be used to form a superlens; but you are essentially correct.
>
> What do you mean by this? A hologram is a very specific interference
> pattern from a multisource laser. How are you forming optical elements from
> this? Typically, a hologram recreates phase information from the original
> two lasers given ambient light ...

What you describe it only one application of holography.

HOE's can serve many functions of conventional optical system; like
combined lens, beamsplitter and spectral filter. Several HOEs may be
formed in the same area of the emulsion so that several can exist
simultaneously. Replication of HOEs is essentially photographic and
therefore simpler than many conventional systems.
Supermarket barcode scanners use a spinning HOE to scan through a volume
at a speed a mechanical system would find difficult or impossible. HUDs
also commonly use them.

> >Surely this is just a detector? As I understood it, an image had to be
> >formed on an array of bolometers. All the thermal imaging cameras I've
> >seen use a lens to image the scene onto the array.
>
> A bolometer is a resistor absorbing incident radiation with or without a
> chopper. Applying a bias voltage allows measurement of the change in
> resistivity, which is directly related to the incident radiation.

I knew that. I don't see how it can image without an optical system.

> Given a
> grid of resistors you can have an imaging device.

No you don't. You have to form at image on the grid. You can't just hold
the array up and get an image. Some sort of optical system is needed,
which is my point.

> >> a photomultiplier tube,
> >
> >Again an image needs to be formed by a lens at the first stage.
>
> Not necessarily. A photomultiplier amplifies incident photons on a
> detector. A lens will focus such, but when detecting faraway galaxies, the
> transmissivity of the lens itself is a concern. Again, an array of fiber
> optic light pipes (which are not lenses) of 99.999% transmissivity can
> direct photons to a photomultiplier or CCD.

You are mistaken. Optical fibres have a 'numerical aperture, or NA. This
determines the acceptance cone and the angular spread of radiation it
may emit.

The solid angle S of the accepting cone is.

S = (approx.) Pi(n1^2-n2^2)

Where n1 is the index of the core and n2 the cladding.

An image *must* be formed on the plane of the fibre-optic faceplate.
This is done via a telescope, the bigger the better. The bigger the
collector the more radiation can be collected and *imaged* to the
detector array.

> >> a fiber-optic array (which is not a classical lens),
> >
> >An image needs to be formed on the plane of the array. The direction of
> >any family of rays entering a fibre will be be completely scrambled when
> >they exit.
>
> Incorrect. First, light pipes tend to preserve vector and phase information
> -- that is their function --

Wrong. Optical fibres do not preserve vector and phase information. A
group of rays incident across the core at a certain angle will not all
emerge at that angle. In fact they will all emerge at different angles.

The function of light pipes is to guide radiant energy from one end to
the other.
I suggest you read 'Optical Guided Waves and Devices' R.R.A. Syms, J.R.
Cozens

> by radially varying indices of reflection and
> internal reflection.

The index difference of cladding and core is slight in most fibres.
Differences of 0.001 are common.

> Second, if phase information is known

But you don't know the phase information of the source. Real world
objects tend to emit incoherent, unpolarised light.

> -- deducible by
> an interferometer or more simply, Fraunhofer lens, then the image vector
> (tensor in the most general case of circular and/or linear polarization) of
> the light can be transformed by the light pipe translation matrix to yield
> final values. That is,
>
> Ma = Pa
>
> Where M is the translation matrix, a is the image vector, and P is the
> sequence of eigenvectors. Given that M is going to be Hermitian for
> real-world examples, you can always find eigenvectors, and hence,
> eigenvalues.

Em-waves travelling down fibres can only do so in a finite number of
allowed modes. This in-itself degrades information as rays traveling in
close but not identical directions will be channeled into the same mode.
Intramodal dispersion and mode conversion caused by imperfections in the
glass would also invalidate the above.

Even in a flawless fibre, variation in effective index arise simply from
the changes in angle between any guided ray and the fibre axis that must
occur with changes in wavelength. This loss of information cannot be
recovered.

> >You have to form an image on one end too get a image out of the other.
>
> See above.
>
> >> a flake of
> >> gallium-arsenide, rhodopsin, etc. etc.
> >
> >Explain?
>
> Band gap properties of this material allow specific photons to be detected.

By what property other than their energy?

> As the band gap can vary, the frequency detectible can as well.

This is directly related to energy. How does this help us image?

> >> Small flat light gathering devices would probably be GaAs based.
>
> >How can you get an image out of these devices without a lens?
>
> Briefly, you can directly convert the photon to a bias voltage, measure the
> array of bias voltages, and reconstruct the image.

A bias voltage does not tell you where the photon came from. A photon
hits a detector, did it come from the Target's head or feet? Your
detector can't give that information.

Light emitted from specific points (x1,y1) on the 'object' must be
mapped to specific detectors on the array (x2,y2). Knowing that a photon
has hit a detector is useless by itself. You need to know where it
originated.

> Then use something like
> bicubic interpolation or least-squares to calculate values in between, for
> more resolution and/or anti-aliasing.

A cross of 100mm by 1mm lines lies at +5 degree azimuth and -10
elevation from the normal of a detector array at 1m. The source is
continuously emitting incoherent polychromatic, unpolarised light.

You can measure the radiant intensity of light falling on each detector
in the array. Describe how, just from this data, you can derive the
direction and shape of the source.

Regards

- David Woods
Message no. 20
From: Thanatos <sthanatos@*********.COM>
Subject: Re: Magnification systems
Date: Sat, 12 Dec 1998 02:41:11 -0500
<snip staggeringly large and scientific discussion>

yes...but can it _butter_ the toast.
Message no. 21
From: Martin Steffens <chimerae@***.IE>
Subject: Re: Magnification systems
Date: Sat, 12 Dec 1998 09:20:07 +0000
[snip huge physics debate]

*grabs a chair and some munchies*

Woohoo, better than Pro-Wrestling!

:)

Martin Steffens
chimerae@***.ie

Further Reading

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Thwap!