HDTenEightyP/NetNews huggingface dataset:
From: vutien@cenatls.cena.dgac.fr (Vu Tien)
Newsgroups: sci.image.processing
Subject: Re: ERS-1 Filters
Date: 28 Jul 92 09:02:29 GMT
Organization: Centre d'Etudes de la Navigation Aerienne
Originator: vutien@coque


In article <1992Jul23.201102.7331@emr1.emr.ca>, naunheim@ccrs.emr.ca (J Naunheimer) writes:
|> 
|> We have recently received some ERS-1 data from the 35-day Multi-disciplinary
|> Phase.  The data were processed to 4 looks in slant range, at a pixel dimension
|> of 35 by 30 metres.
|> 
|> We are interested in filtering the data for display purposes, and we were
|> wondering if any other research groups have investigated filter types and 
|> sizes which maintain radiometric and geometric quality, but effectively 
|> reduce speckle.
|> 
|> If anyone has any information or success stories with using filtering
|> algorithms on ERS-1 data, my collegues and I would appreciate you sharing
|> them.
|> 

Speckle reduction in ERS-1 images (and SAR images) are performed by using a low pass
filter of any kind, which means :
  a) using multi-looks images (summing independant pixels)
  b) performing low pass filtering (loosing resolution)
  c) using a MAP filter (Maximum A Priori Probablility) developed by the CESR team
     Touzi, Lopes, Nezri, et al. (cf IGARSS proceedings, 1990-91-92)

     they can be reached by snail mail at
     CESR, avenue du colonel Roche
     31055 Toulouse Cedex, France.

     There is also a paper in the ESA free bulletin Earth Remote Sensing of July 92
     (or is it August ?)
--
vutien@cenatls.cena.dgac.fr
vutien@capsogeti.fr
Newsgroups: sci.image.processing
From: warnock@Hypatia.gsfc.nasa.gov (Archie Warnock)
Subject: Re: Mathematical morphology for Image Compression???
Organization: Goddard Space Flight Center
Distribution: na
Date: Tue, 21 Jul 1992 19:52:15 GMT

In article <1992Jul20.202315.7143@ultb.isc.rit.edu>, jch3254@ultb.isc.rit.edu (J.C. Handley ) writes:
|>    I asked my advisor, Ed Dougherty, about morphological image
|>    processing being used for image compression.  He said to his 
|>    knowledge there has been no fruitful use of morphology for image
|>    compression.   

I don't have the exact reference handy right now, but there was a paper
on exactly that topic in the new journal "Experimental Astronomy"
sometime last year, in the second or third issue.

See also "An Algorithm To Smooth And Find Objects In Astronomical
Images", Lea & Kellar, Astronomical Journal v97, p1238 (1989).  It's not
about compression, but it has a nice intro to the technique.

-- 
----------------------------------------------------------------------------
-- Archie Warnock                   Internet:  warnock@hypatia.gsfc.nasa.gov
-- Hughes STX                       "Unix --- JCL For The 90s"
-- NASA/GSFC
From: gst5@igpho (Li)
Newsgroups: sci.image.processing
Subject: Re: Buying a lens
Date: 24 Jul 92 11:38:17 GMT
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: Tin 1.1 PL3


Assuming the active dimension of the camera sensor array is R,
object diameter is r, and camera distance is a. Then we have,

      focal_length = a * R / (R + r).

Haihong Li

gst5@p.igp.ethz.ch
From: vayda@csd630a.erim.org (Alan Vayda)
Newsgroups: sci.image.processing
Subject: Re: Hardware for morphological operations
Date: 24 Jul 92 12:23:47 GMT
Organization: Environmental Research Institute of Michigan, Ann Arbor, Michigan
In-reply-to: mychen@acsu.buffalo.edu's message of 24 Jul 92 08:06:44 GMT


ERIM sells (actually fabricates to order) a machine which was designed
here called the Cytocomputer (cyto as in cellular).  While it is
available as a standalone workstation, there is also a VME board
available which has many of the capabilities of the workstation.  I
don't know the price but I expect its very expensive.  I can put you
in touch with someone who knows more about it. 

Applied Intelligent Systems, Inc. (AISI) is located in Ann Arbor.
They sell a number of Vision Computer products which are quite nice
and reasonable priced.
AISI
110 Parkland Plaza
Ann Arbor, MI 48103
(313)995-2035
(you can talk to Jim Anderson (president) or Steve Wilson)


Alan Vayda
vayda@erim.org
(313) 994-1200 x3352
(313) 994-0944 (FAX)
ERIM
PO Box 134001
Ann Arbor, MI 48113-4001
Newsgroups: sci.image.processing
From: ritley@uimrl7.mrl.uiuc.edu ()
Subject: SUMMARY: IMAGE PROCESSING SOFTWARE 1/2
Reply-To: ritley@uiucmrl.bitnet ()
Organization: Materials Research Lab
Date: Sun, 26 Jul 1992 23:41:11 GMT


I recently spotted a summary of image processing software
which was posted to several newsgroups before, I believe,
the sci.image.processing newsgroup was created.

Hopefully it will have some appeal to readers of this
newsgroup.


Article 3084 of sci.geo.meteorology:
Xref: ux1.cso.uiuc.edu sci.geo.geology:1950 sci.geo.meteorology:3084
From: alien@essex.ac.uk ("Adrian F Clark")
Newsgroups: sci.image.processing
Subject: Re: ISO standards
Date: 29 Jul 92 08:10:26 GMT
Organization: University of Essex, UK
In-reply-to: tom@asi.com's message of 27 Jul 92 23:36:15 GMT

Speaking as one of the document editors of this standard, let me say a
few words which I hope will be representative of the imaging group as
a whole.

We (the imaging group) are keen for information on the standard to be
disseminated as widely as possible, and that could include, for
example, making the documents available in machine-readable form,
probably as PostScript.  We are certainly discussing the matter.
However, we are somewhat constrained in this by the rules under which
ISO operate.  For example, when documents reach draft international
standard stage, ISO owns the copyright and electronic (=> free)
distribution to the `general public' (i.e., anyone not involved in the
national or international standardization process) may be prohibited:
the sale of standards documents helps finance most national standards
bodies.

A few comments on things people have said:

> The ISO standards are the Programmer's Imaging Kernel System.

No.  PIKS is only one part of "Image Processing and Interchange", the
other -- and equally important -- part being the "Image Interchange
Format".  However, measured in pages, PIKS wins, with 850 vs 113!

> They
> are currently being reviewed in the US by ANSI committee X3H3.8, the
> next meeting of which is being held in Lowell, MA, August 10-12.

It is also being reviewed by all other ISO `P' members.  A vote on the
Committee Draft documents will complete on 4th Sept, and the next ISO
imaging meeting will be in October in Germany.  Another draft should
follow that meeting -- but whether it will be a second Committee Draft
or a Draft International Standard depends on national bodies'
comments.

> The only public reference I have to this work is...

There are papers by all three document editors in Proc SPIE vol 1659.
I also wrote a short status report which I posted to comp.graphics
some months ago: if anyone would like a copy, please contact me (I
shan't post it unless I'm overwhelmed with requests).

For interested parties, there will be a one-day introduction to IPI at
the Eurographics conference in Cambridge (UK) in early September.  I'm
too modest to say who will be giving it.  I shall try to negotiate
with Eurographics to let me make the notes publically available.

Please feel free to contact me if you have any questions (or post them
to the newsgroup: I guess there are other people who are interested).

--
 Dr Adrian F. Clark                                   JANET: alien@uk.ac.essex
 INTERNET: alien%uk.ac.essex@nsfnet-relay.ac.uk          FAX: (+44) 206-872900
 BITNET: alien%uk.ac.essex@ac.uk              PHONE: (+44) 206-872432 (direct)
 Dept ESE, University of Essex, Wivenhoe Park, Colchester, Essex, C04 3SQ, UK.
Newsgroups: sci.image.processing
From: mcmahan@netcom.com (Dave Mc Mahan)
Subject: Looking for CCD imager sources
Date: Tue, 28 Jul 92 01:36:13 GMT
Organization:  Dave McMahan @ NetCom Services 

A friend and I are attempting to build a CCD imaging system for his
homebrew telescope.  We are looking for imaging chips to perform the actual
photon-to-bits conversion.  As such, we are looking for manufacturers and
outlets for the imaging CCD.  We would like to get _at_least_ 200x200
resolution from the chip.  We plan on adding a thermo-electric cooler to
the chip to cut down on thermal noise.  Please let me know of your favorite
part and/or sources for CCD imaging equipment that might be useful for us.
We plan on rolling our own control circuitry if we can't find a controller
that fills our needs, but the actual imaging chip is currently our most
crucial need.  We are also looking for things like color filters (optical
grade), CCD controllers, mounts, and other accessories.

FYI - The main mirror of the telescope is 13 inches.  Preliminary
      indications are that the mirror is quite excellent, but we still have
	  to get it back from the final silvering process.

Please send any pointers, info, advice, phone numbers, etc. via e-mail.

   -dave

-- 
Dave McMahan                            mcmahan@netcom.com
					{apple,amdahl,claris}!netcom!mcmahan

Newsgroups: sci.image.processing
From: fester@island.COM (Mike Fester)
Subject: Re: Image processing package...
Organization: /usr/local/rn/organization
Date: Tue, 28 Jul 1992 17:36:33 GMT

In article <1992Jul26.163849.2216@jussieu.fr> kbs@ccr-p6.ccr.jussieu.fr (Khac-Binh SU p5717) writes:
>In article <edjans01.711996751@starbase.spd.louisville.edu> edjans01@starbase.spd.louisville.edu (David Jansing) writes:
>>In <1992Jul24.113320.8898@uoft02.utoledo.edu> jarney@jupiter.cse.utoledo.edu (jonathan arney) writes:
>>>  Plans are in the making for other routines such as Forier filtering routines.
>I'd be really interested in the Fourrier routine.

You should get the book _Numerical Recipes in C_ by Press, Flannerey, et al,
Cambridge Press. Has very good Fourier routines. You'll need the smaller 
_Numerical Recipes Example Book_ as well. A MUST for all IPers.

>I'm myself writing a package and built several routines already, as histogram,
>convolution, contrast stretching and a got a source code for a U*ix GIF
>reader and got it work on my PC with Turbo C 2.0.

They sell a disc in MS-DOS format; you can simply copy the relevant code.

Mike
-- 
Disclaimer - These opiini^H^H damn! ^H^H ^Q ^[ .... :w  :q  :wq  :wq! ^d  X ^?
exit X Q  ^C ^? :quitbye  CtrlAltDel   ~~q  :~q  logout  save/quit :!QUIT
^[zz ^[ZZZZZZ ^H  man vi ^@  ^L  ^[c  ^# ^E ^X ^I ^T ? help  helpquit ^D  ^d 
man help ^C ^c help exit ?Quit ?q CtrlShftDel "Hey, what does this button d..."
Newsgroups: sci.image.processing,comp.graphics
From: pjn@phsun.ph.kcl.ac.uk (Philip J. Naylor.)
Subject: Re: Noise Reducing w/ Edge Enhancement
Organization: King's College London
Date: Mon, 27 Jul 1992 10:39:41 GMT
X-Posted-From: phsun.ph.kcl.ac.uk
X-Posted-Through: sol.ctr.columbia.edu

In article <1992Jul27.021555.24987@cs.brown.edu>, jle@dam.brown.edu (Jon Elion) writes:
|> Would be interested in from anyone who has experience with image
|> filtering techniques for noise reduction that simultaneously ENHANCE
|> edges.  Normally, these two operations are mutually exclusive (as
|> noise reduction can tend to BLUR edges, not sharpen them).  There
|> exist non-linear approaches that achieve this goal (although
|> tending to be computationally very intensive).
|> 
	I had good success with the modified trimmed mean (MTM) filter :

Y H Lee & S A Kassam - Generalized Median Filtering and Related Nonlinear
Filtering Techniques, IEEE Trans. Acoustics Speech & Signal Processing, vol. 33,
no. 3, June 1985, pp 672 - 683.

	This is compared with other, similar, techniques in :

Y-H Lee & S Tantaratana - Decision-Based Order Statistics, IEEE Trans. ASSP, 
vol. 38, no. 3, March 1990, pp 406 - 420.

	As originally formulated the filter is one dimensional (and this is the
form in which I used it), but the second paper shows results of its use in 2-D,
presumably by applying it in one direction and then the other.


								Philip J. Naylor.
Newsgroups: sci.image.processing
From: pss1@kepler.unh.edu (Paul S Secinaro)
Subject: Re: Datacube
Organization: University of New Hampshire  -  Durham, NH
Date: Wed, 22 Jul 1992 13:58:19 GMT

In article <SCHULTZ.92Jul21200306@halley.est.3m.com> schultz@halley.est.3m.com (John C. Schultz) writes:
>
>The software may or may not be worthwhile.  MAXWARE was generally considered
>worthless because of bugs although some companies (Innovision perhaps?) fixed
>the bugs and got proprietary versions working.  IMAGEFLOW is apparently much
>better but I have no first hand experience with that.  We made our own
>environment for interactively programming the earlier boards as did most of
>the people using the early Datacube hardware.

Imageflow is pretty nice (though admittedly I don't have experience
with any comparable packages).  Takes a bit of time to learn the
programming model, but once you do it's pretty easy to control the
hardware.

>The biggest conceptual problem with the MAXVIDEO cards is that timing is
>EVERYTHING.  Programming is OK, but you have to get the timing correct so that
>the two desired pixels arrive at the adder (or whatever) at the same 10ns
>increment relative to the RS170 H and V timing.  The easiest way with the
>older boards such as you have is to simply make a function which allows you
>interactive control of the delay lines and FRAMESTORE precess.  Then adjust
>these interactively to get what you want.

Fortunately, Imageflow eliminates all of this.  You just tell it how
to connect the pipelines using dqConnect() calls and the like, and
then "arm" and "fire" the pipeline.  It takes care of setting up all
delays, gateway parameters, etc.

Paul


-- 
Niven's Law #14:   There exist minds that think as well as you do, but
                   differently.
Niven's Corollary: The gene-tampered turkey you're talking to isn't
                   necessarily one of them.
Xref: sparky sci.image.processing:154 comp.compression:2768
From: spl@alex.uucp (Steve Lamont)
Newsgroups: sci.image.processing,comp.compression
Subject: Re: Some common algorithms
Date: 21 Jul 1992 22:31:21 GMT
Organization: University of Calif., San Diego/Microscopy and Imaging Resource
Distribution: usa
NNTP-Posting-Host: alex.ucsd.edu

In article <1992Jul21.193508.14046@csi.uottawa.ca> giridhar@genie.uottawa.com (Giridhar Iyengar) writes:
>I am looking for code of some of the matrix algorithms like Singular
>value decomposition, matrix inversions etc. Does anybody of you know 
>of any ftp sites where I can find these ? 

I'd first take a look at the stuff in _Graphics Gems I & II_.  There are
a few things there in the Matrix Techniques sections.  Source code is
available from weedeater.math.yale.edu and several other of your favorite
FTP sites.

_Numerical Recipes_ by Press, _et_al_, also has some example source
code, though the code is either in FORTRAN or C that appears to be
mechanically translated from FORTRAN.  The sources aren't available on
an FTP site that I'm aware of, being copyrighted by the authors and
sold on a diskette along with the book.  Some of the algorithms aren't
terribly efficient but most of them work as advertised.

							spl
-- 
Steve Lamont, SciViGuy -- (619) 534-7968 -- spl@dim.ucsd.edu
UCSD Microscopy and Imaging Resource/UCSD Med School/La Jolla, CA 92093-0608
"Out of the ash/I rise with my red hair/And I eat men like air."
                        - Sylvia Plath, "Lady Lazarus"
From: spl@alex.uucp (Steve Lamont)
Newsgroups: sci.image.processing
Subject: Re: Image processing package...
Date: 29 Jul 1992 18:37:03 GMT
Organization: University of Calif., San Diego/Microscopy and Imaging Resource
NNTP-Posting-Host: alex.ucsd.edu

In article <MANNING.92Jul29115240@halley.est.3m.com> manning@halley.est.3m.com (Arthur T. Manning) writes:
>I have uploaded all the Numerical recipes source code to my Sun.  I'd be
>happy to ftp it all to a public site.  Where should I send it?

To /dev/null?  :-)

I believe that the software is copyrighted and you'd be in violation
of copyright law by doing so.

							spl


-- 
Steve Lamont, SciViGuy -- (619) 534-7968 -- spl@dim.ucsd.edu
UCSD Microscopy and Imaging Resource/UCSD Med School/La Jolla, CA 92093-0608
"Out of the ash/I rise with my red hair/And I eat men like air."
                        - Sylvia Plath, "Lady Lazarus"
Newsgroups: sci.image.processing
From: IMAGING.CLUB@OFFICE.WANG.COM ("Imaging Club")
Subject: Wang SEAVIEW open document imaging
Organization: Mail to News Gateway at Wang Labs
Date: 28 Jul 92 12:11:04 EST

If you'd like a copy of that Wang SEAVIEW open
document imaging news from the AIIM imaging
show in June, let me know.

Michael.Willett@OFFICE.Wang.com
Newsgroups: sci.image.processing
From: eha@phoenix.oulu.fi (Esa Haapaniemi)
Subject: Re: VICAR greyscale to color
Organization: University of Oulu, Finland
X-Newsreader: Tin 1.1 PL4
Date: Mon, 20 Jul 92 08:32:05 GMT

rroman@casbah.acns.nwu.edu (Randall Roman) writes:
> Has anyone done any image processing on VICAR images from the
> Magellan mission to Venus? 

I saw some pictures converted to Amiga 24IFF pictures, and there
was some notes on doing it, but I cannot remember the place they
were in. (Prosessing was done on mainframes, not Amiga).

Esa Haapaniemi
University of Oulu
Finlan
Newsgroups: sci.image.processing
From: rchann@qucis.queensu.ca (Robert Chann)
Subject: Re: Datacube
Organization: Computing & Information Science, Queen's University at Kingston
Date: Thu, 23 Jul 1992 13:54:48 GMT

In article <1992Jul20.225917.2880@ohsu.edu> bellutta@cascade.ohsu.EDU (Paolo Bellutta) writes:
>In article <1992Jul20.221850.11457@ctr.columbia.edu>  
>sion@sioux.ctr.columbia.edu (Boudi Sahyoun) writes:
>> 
>> Any datacube experts around here?
>
>There is a datacube mailing list. To be added to the list send e-mail to:
>datacube-list@media-lab.media.mit.edu

I thought it was "datacube-request@cs.uchicago.edu"!?!  I sent an "add me"
message to this address a few days ago and it worked for me.

Rob
 
-- 
=============================================================================
Robert Chann
Queen's University                       Phone:  (613)545-6693
Kingston, Ontario, Canada                Email:  rchann@eleceng.ee.queensu.ca
From: johnson@akula.llnl.gov (  Robert Johnson          )
Newsgroups: sci.image.processing,comp.graphics
Subject: Frame Grabbers
Date: 22 Jul 92 16:21:05 GMT
Reply-To: johnson@akula.llnl.gov (  Robert Johnson          )
Followup-To: sci.image.processing
Organization: Lawrence Livermore National Laboratory

I am looking for information/recommendations on frame
grabbers for both the Sun SPARCstation (2,10) and the
PC (386,486) platforms.  At this time, I am basically
looking for a low cost method to grab frames of a
broadcast UHF signal.  It would be nice if I could
simply utilize C function calls to aquire frames
into memory as 8 bit intensity images so that I could
then pass them on to other C functions for image processing.
Frame rate is not really a major concern at this time.
Ultimately, it would be nice to have Datacube like
capabilities for real-time hardware image processing, but
current budget limitations dictate a low end solution.
I prefer to use my Sun but I am also interested in info for
the PC.  Please respond by E-mail.  Thanks in advance.

-----------------------------------
Robert K. Johnson
Lawrence Livermore National Lab
Phone: (510) 422-8375
Email: johnson60@llnl.gov
From: foodeei@INRS-Telecom.UQuebec.CA (Majid Foodeei)
Newsgroups: sci.image.processing
Subject: Re: Mathematical morphology for image compression
Date: 21 Jul 92 14:32:59 GMT
Organization: INRS Telecommunications

I'm also interested in any such algorithms. I would appreciate receiving any 
post or email responses.

                          Thanks, Majid (foodeei@inrs-telecom.uquebec.ca)
 

-- 
Majid Foodeei     foodeei@inrs-telecom.uquebec.ca
Department of Electrical Engineering
McGill University, 3480 University Street  (514) 761-8646
Montreal, Quebec  Canada H3A 2A7           (514( 761-8501 (FAX)
Newsgroups: sci.image.processing
From: brabec@pysgjb.physics.ncsu.edu (Charles Brabec)
Subject: Re: Filter Ranges for Enhancement, HELP!?!
Organization: NCSU Physics, Condensed Matter Theory
Date: Mon, 27 Jul 1992 03:24:04 GMT

In article <1992Jul27.100116.9655@waikato.ac.nz> singlis@waikato.ac.nz writes:
>Greetings,
>
>when filtering with a standard Laplacian filter
>	[ -1  -1  -1 ]
>	[ -1   8  -1 ]
>	[ -1  -1  -1 ]
>and assuming the pixel values from 0..1 in intensity, the result of the 
>operation can range from -8.0 to 8.0. What is the standard way of
>mapping this result to a pixel range.
>
>I have tried just diving by 8.0, and if negative ignore but this just gives
>"black" images, I also tried /8.0 and the absolute, still it looks terrible.
>
>Could anyone give me some tips??

Scale the result of the filter as you like, then add to it the value of the
central pixel and clip the results to your pixel range.

So for example, using the 1/8th filter on the pixels (range = 0-256)
      16  16  16
      32  32  32
      64  64  64

your filter value is: 32 - 2 - 2 - 2 - 4 - 4 - 8 - 8 - 8 = -6
Added to your original value: 32 + (-6) = 26
so 26 is your new value.

If your pixels were:
       0  0  0
       0  0  0
      16 16 16
your filter value is: 0 - 0 - 0 - 0 - 0 - 0 - 2 - 2 - 2 = -6
Added to your original value: 0 + (-6) = -6
Clip to the range: = 0
so 0 is your new value.

Experiment with the scaling of the Filter to increase or decrease the amount 
of edge enchancement. 1/8th and 1/16th are good to try, especially if you're
doing integer math.

Charles
-- 
--------------------------------------------------------------
Charles Brabec 					304 Cox Hall
brabec@pysgjb.physics.ncsu.edu			(919) 515-7228
From: spl@ivem.uucp (Steve Lamont)
Newsgroups: sci.image.processing
Subject: Re: Filter Ranges for Enhancement, HELP!?!
Date: 27 Jul 1992 01:48:50 GMT
Organization: University of Calif., San Diego/Microscopy and Imaging Resource
NNTP-Posting-Host: ivem.ucsd.edu

In article <1992Jul27.100116.9655@waikato.ac.nz> singlis@waikato.ac.nz writes:
>when filtering with a standard Laplacian filter
> ...
>and assuming the pixel values from 0..1 in intensity, the result of the 
>operation can range from -8.0 to 8.0. What is the standard way of
>mapping this result to a pixel range.
>
>I have tried just diving by 8.0, and if negative ignore but this just gives
>"black" images, I also tried /8.0 and the absolute, still it looks terrible.

How about 

	new_pixel_value = ( old_pixel_value + 8.0 ) / 16.0

?

This puts the pixels back into a 0..1 intensity range.

							spl
-- 
Steve Lamont, SciViGuy -- (619) 534-7968 -- spl@dim.ucsd.edu
UCSD Microscopy and Imaging Resource/UCSD Med School/La Jolla, CA 92093-0608
"Out of the ash/I rise with my red hair/And I eat men like air."
                        - Sylvia Plath, "Lady Lazarus"
Newsgroups: sci.image.processing
From: woelker@tnt.uni-hannover.de ( Wolfgang Woelker )
Subject: Re: NEEDED: ftp site w. TIFF conversion/manip. l
Reply-To: woelker@tnt.uni-hannover.de
Organization: Universitaet Hannover, Theoretische Nachrichtentechnik
Date: Fri, 31 Jul 1992 07:15:41 GMT

In article 23191@leland.Stanford.EDU, felciano@summit.stanford.edu (Ramon Felciano) writes:
>Hi!
>
>I'm trying to get ahold of some TIFF manipulation and conversion routines. Someone told
>me there was an ftp site in Berkeley that had a large TIFF library. Does anyone know of
>this?
>
> ...

The software you are looking for is from Sam Leffler and it's
available for public ftp on

    sgi.com			graphics/tiff
	(192.48.153.1)
and
    ucbvax.berkeley.edu		pub/tiff
	(128.32.130.12)

Hope this helps
---

      \    /                            woelker@tnt.uni-hannover.de
  \    X/\/oelker
   \/\/olfgang                          fax:    +49-511-762-5333
                                        ISDN:   +49-511-971007-0 (voice)
  Universitaet Hannover
  Institut fuer Theoretische Nachrichtentechnik und Informationsverarbeitung