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Re: ellipse fitting? [message #30516 is a reply to message #30371]

Sat, 27 April 2002 17:58

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

tom (tom2959@21cn.com) writes:

> I found a matlab function for ellipse, but it is not easy for me translate
> to IDl. For example,
>
> % Solve eigensystem
> [gevec, geval] = eig(S,C);
>
> are there any function like eig(S,C) in IDL?
>
> The matlab for ellips fitting is as following, who have a idl version?

I've put a new IDL program named FIT_ELLIPSE on my
web page:

http://www.dfanning.com/programs/fit_ellipse.pro

In true IDL programmer fashion, I've used the ideas
of others to create something useful to me.
In this case, I'm particularly grateful to Craig
Markwardt, who wrote the eigenvalue part of the code
as a favor to me, and to Wayne Landsman, whose program
TVEllipse I've used for a long time. You can find this
program on the NASA Goddard IDL web page.

The Fit_Ellipse function accepts a 1D array of pixel
indices, and returns the points that describe the
fitted ellipse in device coordinates. The format of
the points is such that they can be sent directly to
PLOTS. Optional keywords allow you to obtain the
center of the ellipse, the orientation of the major
axis, and the major/minor or the semi-major/semi-minor
axes.

Cheers,

David

--
David W. Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

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[Message index]

		ellipse fitting? By: tom on Sat, 27 April 2002 06:52
		Re: ellipse fitting? By: hradilv.nospam on Mon, 29 April 2002 09:19
		Re: ellipse fitting? By: Craig Markwardt on Sun, 28 April 2002 07:51
		Re: ellipse fitting? By: David Fanning on Sat, 27 April 2002 17:58
		Re: Ellipse fitting? By: David Gell on Wed, 13 May 2009 06:18
		Re: Ellipse fitting? By: Kenneth P. Bowman on Tue, 12 May 2009 15:10
		Re: Ellipse fitting? By: David Fanning on Tue, 12 May 2009 14:18

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