Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V10_0/V10_054.ZIP/V10_054

Internet Message Format | 1991-07-08 | 16KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/sZ53QJa00jaSE99E4J>;
          Sun, 17 Sep 89 20:30:14 -0400 (EDT)
Message-ID: <[e-mail]>
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Sun, 17 Sep 89 20:29:49 -0400 (EDT)
Subject: SPACE Digest V10 #54

SPACE Digest                                      Volume 10 : Issue 54

Today's Topics:
         NASA Headline News for 09/08/89 (Forwarded)
           Re: How the "Face" imaging data was pro
             Re: NASA missions/time table
  Re: NASA designates 17 space grant colleges/consortia (Forwarded)
            Re: Linguistic Tidbits
            Re: Linguistic Tidbits
          How the "Face" imaging data was processed
        Neptune images - help with MAC-II data format
        Re: How the "Face" imaging data was processed
----------------------------------------------------------------------

Date: 8 Sep 89 19:06:01 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 09/08/89 (Forwarded)

-----------------------------------------------------------------
                          NASA Headline News
Friday, Sept. 8, 1989                         Audio: 202/755-1788
-----------------------------------------------------------------


This is NASA Headline News for Friday, September 8....


Workers at Kennedy Space Center's Pad 39B are conducting a
payload End-to-End Test today.  The test is an important
milestone in preparing for the Countdown Demonstration Test
scheduled for next Thursday and Friday.  The crew arrives at the
Cape Tuesday evening.


Two Soviet cosmonauts have begun to reactivate the Mir Space
Station.  Tass news agency reports that Alexander Viktorenko and
Alexander Serebrov began to power up the spacecraft shortly after
2:00 A.M., Moscow time.  Some problems were experienced in the
automatic docking procedure and the cosmonauts were required to
do the linkup under manual control.

A Progress-M resupply vehicle preceeded the arrival of the Soyuz
in late August.  The two-man crew began to unload the Progress
almost immediately.  The pair of cosmonauts will be aboard the
station for six months.  Special modules will be launched in
October and February to expand the working area of the station.


The University of Alabama-Huntsville Consortium for materials
development in space has set November 12 as the launch date for
their second flight this year.  Space Services of Houston will
provide the sounding rocket which will take 12 microgravity
experiments on a suborbital flight from the White Sands Missile
Range in New Mexico.  The rocket will reach 200 miles altitude,
giving the experiment package seven to eight minutes of
weightlessness.


NASA's Ames Research Center, Genentech and Penn State
University's Center for Cell Research will join in a program to
expand understanding of the effects of microgravity on the human
body.  It's been found that microgravity accelerates reduction in
bone calcium, body mass and immune cell function.
It's hoped that the program, scheduled to start in 1990, will
increase medical knowledge to treat human bone diseases, organ
regeneration and transplantation as well as immune and skeletal
muscle cell deficiency.


              *           *          *          *



-----------------------------------------------------------------
Here's the broadcast schedule for public affairs events on NASA
Select television.   All times are Eastern.



Thursday, September 14.....

     11:30 A.M.       NASA Update will be transmitted.


Friday, September 15.....

      6:00 A.M.       Final six hours of the STS-34 Countdown
                      Demonstration Test with astronaut crew.


All events and times are subject to change without notice.

-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon,
Eastern time.

-----------------------------------------------------------------

A service of the Internal Communications Branch (LPC), NASA
Headquarters.

------------------------------

Date: 8 Sep 89 19:26:00 GMT
From: tank!eecae!upba![e-mail]
Subject: Re: How the "Face" imaging data was pro



How about posting the reference to the original paper?

------------------------------

Date: 10 Sep 89 02:59:59 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: NASA missions/time table

In article <[e-mail]> [e-mail] (Terry Hancock) writes:
>    How would the RTGs handle an extreme high velocity reentry (or
>atmosphere - crossing orbit, it might still leave the atmosphere of
>course)?  ...

This is actually considered the worst reasonably-likely accident (since
it takes pretty unlikely ones to break the RTGs open during launch).
I believe the RTGs aren't tough enough to survive high-speed reentry plus
impact intact.
--
V7 /bin/mail source: 554 lines.|     Henry Spencer at U of Toronto Zoology
1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry [e-mail]

------------------------------

Date: 10 Sep 89 03:21:16 GMT
From: ibmpa![e-mail]  (nick szabo)
Subject: Re: NASA designates 17 space grant colleges/consortia (Forwarded)

In article <[e-mail]> [e-mail] (Peter E. Yee) writes:

[$75K first year, $225K+$100K fellowships in succeeding years for each
college/consortia]

This sounds great!  The number of colleges and the dollar amounts look kind
of small, though.  Also, what will be the scientific and technical
emphasis of the funded research?  The press release only mentioned
"engineers and space scientists".

"Want oil?   Drill lots of wells."
        J. Paul Getty

--
--------------------------------------------
Nick Szabo
uunet!ibmsupt!szabonj
These opinions are not related to Big Blue's

------------------------------

Date: 12 Sep 89 18:33:04 GMT
From: dinl![e-mail]  (kevin w. holroyd)
Subject: Re: Linguistic Tidbits

In article <[e-mail]> [e-mail] (Jonathan McDowell) writes:    stuff deleted
>
>How about the rest of the solar system? I think that it's
>Mercury:    perihermes    aphermes
>Venus:        ?
>Mars:        periares    apoares
>Jupiter:    perizenon?
>Saturn:        perikronon?
>
>Any offers from classical scholars?

Venus:        ?        ap  hrodite :-) :-)

--
*******************************************************************************
Kevin W. Holroyd            *
CFI Aspen Flying Club            * Got tired of last .signature file
Denver CO.                *
*******************************************************************************

------------------------------

Date: 12 Sep 89 21:12:27 GMT
From: bbn.com![e-mail]  (Nichael Cramer)
Subject: Re: Linguistic Tidbits

In article <[e-mail]> [e-mail] (kevin w. holroyd) writes:
>In article <[e-mail]> [e-mail] (Jonathan McDowell) writes:    stuff deleted
>>
>>How about the rest of the solar system? I think that it's
>>Mercury:    perihermes    aphermes
>>Venus:        ?
>>Mars:        periares    apoares
>>Jupiter:    perizenon?
>>Saturn:        perikronon?
>>
>>Any offers from classical scholars?
>
>Venus:        ?        ap  hrodite :-) :-)

I like this.

As a brief aside, somewhere ("Intelligent Life in the Universe" ?) Sagan
suggests the adjective "Cytherean" --from Cytherea, the island where
Venus/Aphrodite was "born"-- to describe things connected with Venus.  In
part because the adjective form of "Venus" is "Venereal" and he refused to
accept the neologism "Venusian".

I always thought this very pretty, but I don't recall ever having seen it
used.

NICHAEL

------------------------------

Date: 8 Sep 89 08:47:34 GMT
From: oliveb!amdahl!drivax![e-mail]  (MacLeod)
Subject: How the "Face" imaging data was processed

Several posters have expressed doubts about the techniques used to resolve
the Martian "Face" imaging data.  I read the original paper which describes
the technique, and I was impressed with its cleverness.  Of course, I have
only a casual background in science, and this technique may be either in
everyday use or obsolete due to better methods.

Anyway, the imaging data is captured as an 8-bit word, yielding 256 shades
of grey.  The researchers took this data, and figuratively expanded each pixel
into a set of nine pixels, as we will see.

                                    -----l-----l-----
First consider a block of           l A  l  B  l  C l
nine adjacent pixels values         l    l     l    l
labeled A through I:                -----l-----l-----
                                    l D  l  E  l  F l
                                    l    l     l    l
                                    -----l-----l-----
                                    l G  l  H  l  I l
                                    l    l     l    l
                                    -----------------

Now consider the middle pixel in this group, E.  The methodology expands
this pixel value into nine values:
                                    -----l-----l-----
                                    l E  l  E  l  E l
       l-----l                      l 1  l  2  l  3 l
       l  E  l  --------->>>        -----l-----l-----
       l     l                      l E  l  E  l  E l
       l-----l                      l 4  l  5  l  6 l
                                    -----l-----l-----
                                    l E  l  E  l  E l
                                    l 7  l  8  l  9 l
                                    -----------------

(Pardon the awful ASCII graphics)

They then used a set of weighting algorithms to assign values to each new
data point.  Pixel E(5) has 100% of the value of the original E,
whatever it was.  Now, pixel E(2) is assigned a value calculated by adding
75% of the value of E(5) to 25% of the value of B(8) [or some
other set of values adding up to 100%].  E(1) is assigned a value
weighted somewhat differently; if E(1) were further broken down into more
values, E(1,1) would logically be expected to have a value closer to A(9,9)
than E(1,9), or E(5,1).  So the weighting algorithm was adjusted to reflect
this.  You can see that it takes several passes to  calculate and recalculate
the correct values, because the first set of calculations must use the "raw"
values for A, B, C, etc. Once preliminary averaged values for A(1-9), B(1-9),
etc. have been resolved, finer calculations can be made.

As I said, I thought this pretty clever. Information theorists tell us that
there ain't no free data, but this comes close to looking like some sort of
software holography yielding higher resolution by magic.  After some
reflection, I decided that if you compared the expanded image to a new image
which actually captured nine times the data of the original image, it would
be clear that what was produced was an average.  Where the "real" data
differed, interestingly, would be in gradations of detail which were (for
our purposes) nonlinear - where an abnormally bright spot was somehow
juxtaposed, for whatever reason, with an abnormally dark one. But there's
nonlinear and nonlinear - if the data added in the "real" high-detail
imaging is nonlinear, can it be thrown away as noise?  I know the answer is
no, but I don't know why with any certainty - possibly because the signal to
noise ratio is so high and the sample range is so small that the distinction
between noise and data is hard to make. I appeal to those of you with
greater experience and knowlege to help me out here and explain the merits and
inherent problems with this fascinating methodology.  (I immediately tried to
apply the concept to digital sound, but didn't get anywhere...but it's an
interesting thought!)

Finally, as kind of a control, the researchers took a heap of 8-bit data
from a terrestrial imaging satellite and processed it.  The resulting image
very closely resembled a photograph taken from a far lower altitude, so
they were encouraged.

The paper contained many images, including the "control", and was quite
entertaining.


Michael Sloan MacLeod  (amdahl!drivax!macleod)

------------------------------

Date: 8 Sep 89 20:54:26 GMT
From: oliveb!tymix!opus![e-mail]  (Bruce Thomson)
Subject: Neptune images - help with MAC-II data format

Can anyone please explain the format of the MAC-II ("ProViz" I believe)
image files in detail?  I would like to write a program to display them.
I don't have a MAC or compatable graphics program

From memory, the descriptions that I saw refered to an array of
"grey-scale" pixels.  Each byte in the file is apparently one pixel.
Does the value of the byte represent a "grey-scale" density?  If this is
the case, the file sizes are too small.  I think that I remember the
images where something like 640 by 480 pixels.  This would result in a
file size of 307200 bytes.  The files vary in size, but some are far too
small if this is the case.

What I need is a clear and detailed description of how the data in the
files maps to the image to be displayed.

I imagine that there are other people like myself that would like to see
these pictures, but don't understand the data structure of the files.

------------------------------

Date: 8 Sep 89 20:39:05 GMT
From: [e-mail]  (Kevin William Ryan)
Subject: Re: How the "Face" imaging data was processed

>  [e-mail] says:
> [ Long description of 3x3 pixel duplication and averaging to blow up the
>   original 'Face' data.  Statement that this appears to "almost be producing
>   new data." ]

   Yeaarg.  Ick.  Well, now that the visceral response is done with...

   When you do pixel duplication expansion of an image (copy original to an
image 3 times the size, with each pixel replicated in a 3x3 area) followed by
averaging (replace each pixel by the average value of its area) YOU DO NOT
PRODUCE NEW DATA!  It may appear that you have a better, more detailed image,
what you have is simply a larger image.  You have not improved resolution
at all.  Nyquist criterion - you can record/reproduce/extract information that
is up to half your sampling frequency.  An image can record details that
have edges containing spacial frequencies up to a wavelength of 2 pixels.
In other words, you can only record an edge that varies from one pixel to
the next.  If you blow up the image by a factor of X you now have an edge
transition that occurs over X pixels.  You have _no_ sharper detail.  Any
edge transition occuring over less than X pixels, however you may manipulate
the data, is empty enhancement.  It wasn't in the original.  If someone
tells you otherwise, they may ask you to buy a bridge next.

   Side note - there are methods of examining the frequency function of an
image, and doing an analytic extrapolation of the function to produce a
resolution greater than sampling, since the frequency function must _be_ an
analytic function.  However, in the presence of even _minimal_ noise, it
fails.  It's only useful in situations of almost unreal S/N ratios, and I
have never heard of anyone considering it except theoretically.  The Nyquist
criterion still holds in the real world.

   To repeat a theme - be careful of what you are claiming for enhancement.
It's easy to pull out almost anything you wish from a sufficiently complex
object with appropriate filtering and enhancement.  Just look at what people
get out of Bible!

                                                   Kevin Ryan
                                                   Asst. Dir. Imaging Tech.
                                                   Biological Sciences
                                                   Carnegie Mellon U.

                                                   [e-mail]

Disclaimer - These statements in no way reflect the policies/opinions of
             CMU, even though I'm right...

------------------------------

End of SPACE Digest V10 #54
*******************