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I was half afraid my little rant on software release issues would bring the
wrath of the newsgroup on me. So far, no flames....<br>
<br>
Here is a ref for an intro to remote sensing;<br>
Remote Sensing and Image Interpretation by Lillesand and Kiefer is a common
introduction to remote sensing. It discusses the basics of image processing
and emphasizes the utilization of satellite imagery. The discussion on filters
is rather qualitative, but adequate for writing some very basic, but effective
imaging software.<br>
Borrow an old copy of it, it is pretty light reading.<br>
<br>
If you desire something more advanced, I'd recommend a good book on digital
signal processing. Everybody seems to have their favorite filters for certain
uses. Amazingly, with the huge variety of existing imaging algorithms available
, it is still a fad for people to write and publish new,(and sometimes radical)
filter algorythms. There is a lot out there, and the amount of material
is growing.<br>
<br>
Glen<br>
<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:dajelen@att.net">dajelen@att.net</a> wrote:<br>
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<p>Hi Glen,</p>
<p> </p>
<p>Thanks for the input.</p>
<p>I do appreciate your position on this and taking the time to respond
to my question.</p>
<p> </p>
<p>Can you recommend book(s) that you've used that explain image processing
that could</p>
<p>get me started with the algorithms? I assume that there are "better"
undergraduate</p>
<p>books on remote sensing and image processing?</p>
<p>My background has been in business (data) processing, rather than numeric
(image)</p>
<p>processing. I consider myself a good programmer who learns quickly.</p>
<p>Is this something I can learn from the book(s)?</p>
<p> </p>
<p>I'm not looking to incur the wrath of whomever, just want to learn image
processing and</p>
<p>parallel programming . . .</p>
<p> </p>
<p>Thanks again,</p>
<p>Dave</p>
<blockquote
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Original message from Glen Gardner <GLEN .gardner@verizon.net="">: --------------
<br>
It looks like you hit the thread just fine.<br>
<br>
By "simple imaging software", I mean low-level image processing. It typically
involves very simple computational tasks, like lowpass filters, highpass
filters , based on convolution masks. These kind of tasks are easily parallelized
and the filters can usually be written by most people in a few hours.<br>
In any case, I have a number of rather simple filters writtien in C for MPI.
I then call the filters in combination using a shell script to do more complex
things. In this way I can use a suite of simple, generic tools in a highly
configurable fashion to perfrom more complex imaging tasks in a wider variety
of situations than I could with a highly specialized (and more complex) program.<br>
<br>
By "embarrassingly parallel" I mean the parallel programs consist of processes
which communicate with each other very little (or not at all).<br>
In the case of my imaging software , it only communicates twice. First to
divide the imaging data into separate jobs for each node, and once more after
processing, to gather and reassemble the "finished" data into an image.<br>
<br>
MPI and PVM are publicly available parallel environments. They provide a
means of communicating between processes. If you install one of them on
a Linux or FreeBSD cluster you can use it with the compilers that came with
the operating system. From there, you pretty much have to write your own
parallel programs.<br>
<br>
The software which I have written is not a GPL release, and and it is not
public domain. I have no plans to release it at this time. But such code
is a very simple thing to write and sufficient information about the basics
of image processing can be found in most undergraduate textbooks on remote
sensing and image processing.<br>
<br>
I feel a need to justify my position on this, so please bear with me.<br>
<br>
There is a general reluctance, on the part of many people (myself included),
to publicly release parallel code due to; the unfortunate federal restrictions
on the export of high performance computing technology, the high dollar value
of good parallel code, and the high rate of plagiarism in the programming
industry. Also, the highly customized nature of Beowulf machines makes it
difficult (or impossible) to be sure that a given parallel program will compile
and run from one Beowulf to the next. Overall, the situation discourages
public releases of parallel code, and is an unhappy impediment to the sharing
of new ideas among high performance computing advocates. <br>
<br>
A lot of people are working to improve the situation, and hopefully there
will eventually be a platform for making official releases of parallel code
that serves to protect the author's rights as well as making more software
available to the public, without upsetting ITAR, homeland security, etc..<br>
<br>
<br>
Glen<br>
<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:dajelen@att.net">dajelen@att.net</a>
wrote:<br>
</GLEN>
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<p>Hi all,</p>
<p> </p>
<p>I receive this maillist as a digest and I wasn't sure how to reply
to this thread.</p>
<p> </p>
<p>I've been eagerly following this thread of what to do with a Beowulf
once it is assembled.</p>
<p> </p>
<p>Glen mentioned imaging software that is very simple and embarassingly
simple.</p>
<p> </p>
<p>Is anything proprietary about this software?</p>
<p>I'd like to learn more about how it works, what it can do, and how
to install/run</p>
<p>it on a Beowulf cluster.</p>
<p> </p>
<p>This is one of the possibilities I've been considering for a Beowulf
cluster and would like</p>
<p>to learn from someone who has already accomplished it.</p>
<p> </p>
<p>Thanks,</p>
<p>Dave</p>
<p> </p>
<p>P.S. To all of you, I really do appreciate the input about books
and classes that you have</p>
<p>provided.</p>
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<pre class="moz-signature" cols="$mailwrapcol">--
Glen E. Gardner, Jr.
AA8C
AMSAT MEMBER 10593
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<pre class="moz-signature" cols="$mailwrapcol">--
Glen E. Gardner, Jr.
AA8C
AMSAT MEMBER 10593
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