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Edge detection for saturn's rings [message #61345]

Mon, 14 July 2008 17:43

frankosuna
Messages: 31
Registered: February 2008

Member

Hello all,

I've been trying to use some of the built in edge detection routines
implemented in idl such as sobel but I haven't found a very good one
that will work for images such as this:

http://frankosuna.googlepages.com/supportImage.jpg

I am trying to pull out all of the rings in this image and the best I
have gotten is this:

http://frankosuna.googlepages.com/edgeDetect.jpg

Any suggestions and opinions are welcome.

Thanks,

Frank

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Re: Edge detection for saturn's rings [message #61377 is a reply to message #61345]

Wed, 16 July 2008 09:10

frankosuna
Messages: 31
Registered: February 2008

Member

Good morning Dr. Fanning,

I received your email and tried to reply but there was an error
sending the email.
I am actually working on my Computer Science Master's Thesis at the
University of Texas at El Paso. The name of my paper, which I am
currently working on, is "Automated C-Smithing". We are working side
by side with NASA and these images are provided by them. The images I
use are actually taken by the Cassini spacecraft currently orbiting
around Saturn and its moons. I don't think I have the freedom to
provide the images I actually use, but I believe there are some images
on their web page. This is the home page where they provide
information about the mission http://saturn.jpl.nasa.gov/home/index.cfm
and here is the web page where some images are shown
http://saturn.jpl.nasa.gov/multimedia/images/images.cfm?star tImage=17&categoryID=1&subCategoryID=0.

Thanks,

Frank

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Re: Edge detection for saturn's rings [message #61389 is a reply to message #61345]

Wed, 16 July 2008 07:06

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Vince Hradil writes:

> I dug around a couple of years ago and found a canny implementation in
> idl. I fixed it up so that it works pretty well for me, but I haven't
> used it in quite a while. The header mentions Julian Walmsley, 1999
> requires IDL 5.2.x - based on Gideon Amos, 1997, requires IDL 4.x.

The one I mentioned was introduced in IDL 6.3.

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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Re: Edge detection for saturn's rings [message #61390 is a reply to message #61345]

Wed, 16 July 2008 07:02

Vince Hradil
Messages: 574
Registered: December 1999

Senior Member

On Jul 15, 10:02 pm, David Fanning <n...@dfanning.com> wrote:
> frankosuna writes:
>> I've been trying to use some of the built in edge detection routines
>> implemented in idl such as sobel but I haven't found a very good one
>> that will work for images such as this:
>
>> http://frankosuna.googlepages.com/supportImage.jpg
>
>> I am trying to pull out all of the rings in this image and the best I
>> have gotten is this:
>
>> http://frankosuna.googlepages.com/edgeDetect.jpg
>
>> Any suggestions and opinions are welcome.
>
> Andrew Cool points out to me that as a backyard astronomer, he
> is always interested in this kind of thing, and that the CANNY
> edge detection routine is often the best one for this kind of
> separation. Oddly, though, there is no mention of the CANNY
> routine under "Edge Detection" in either the IDL 6.4 or IDL 7.x
> on-line help! An oversite we hope someone at ITTVIS notices.
>
> Cheers,
>
> David
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")

I dug around a couple of years ago and found a canny implementation in
idl. I fixed it up so that it works pretty well for me, but I haven't
used it in quite a while. The header mentions Julian Walmsley, 1999
requires IDL 5.2.x - based on Gideon Amos, 1997, requires IDL 4.x.

Cheers,
Vince

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Re: Edge detection for saturn's rings [message #61406 is a reply to message #61345]

Tue, 15 July 2008 20:02

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

frankosuna writes:

> I've been trying to use some of the built in edge detection routines
> implemented in idl such as sobel but I haven't found a very good one
> that will work for images such as this:
>
> http://frankosuna.googlepages.com/supportImage.jpg
>
> I am trying to pull out all of the rings in this image and the best I
> have gotten is this:
>
> http://frankosuna.googlepages.com/edgeDetect.jpg
>
> Any suggestions and opinions are welcome.

Andrew Cool points out to me that as a backyard astronomer, he
is always interested in this kind of thing, and that the CANNY
edge detection routine is often the best one for this kind of
separation. Oddly, though, there is no mention of the CANNY
routine under "Edge Detection" in either the IDL 6.4 or IDL 7.x
on-line help! An oversite we hope someone at ITTVIS notices.

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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