Re: Help! Need Best-Fit Circle Equation.

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#22

From: Peter Spellucci
Date: Thu, 02 Apr 1998 00:00

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In article <3523A24A.F9C10F3B@conversionsinc.com>, Kurt Feldbush <kurt@conversionsinc.com> writes:
|>     I am looking for an equation or algorithm to find the best fit
|> circle or ellipse to a set of data points.  I have searched everywhere I
|> could think of with no luck.  Can anyone help?
|> 
take odrpack from netlib. there is an ellipse-fit in the user-guide,
and, of course, the circle is the simpler case. you could do the
circle fit in a special manner (not using general orthogonal regression)
simply by minimizing 

   sum_i { ( (x_i-xm)**2+(y_i-ym)**2-r**2 )**2 }

with respect to xm,ym and r (midpoint and radius), with x_i,y_i the
given points
hope this helps
peter

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From: spellucci@mathematik.th-darmstadt.de (Peter Spellucci)
Subject: Re: Help! Need Best-Fit Circle Equation.
Date: 1998/04/02
Message-ID: <6g0ib2$16a$1@sun27.hrz.tu-darmstadt.de>
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References: <3523A24A.F9C10F3B@conversionsinc.com>
To: Kurt Feldbush <kurt@conversionsinc.com>
Organization: TH Darmstadt, Fachbereich Mathematik
Newsgroups: sci.stat.math,sci.math.num-analysis,aus.mathematics

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