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Re: fitting mixed gaussians [message #44139 is a reply to message #44138]

Tue, 17 May 2005 11:32

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Ben Tupper writes:

> I would like to employ a "mixed gaussian" fitting routine that fits not
> just one peak in a distribution but rather fits any number of peaks.
> According to my old Gonzales and Woods Image Processing book this
> technique is used in Bayesian classifier - in the two class problem the
> saddle of the two fitted curves is used as the point around which the
> classes are separated. I just to segment simple grayscale images with it
> usiing the histogram as the data to model.
>
> Using GAUSSFIT or MPFIT it's very easy to fit one (the tallest) peak
> shown in the example (see code example below.) But how the heck to fit
> the second peak? I have scoured the internet and find much written
> about it - but it is all in Greek. Really. Yikes.
>
> Is it possible to make the curve fitting routines I have on hand to fit
> two gaussian models?

Craig is going to fill you in on all the details of this,
using MPFIT, but I just wanted to mention that Rob Dimeo's
PAN program is super for allowing you to fit as many curves
as you like onto a set of data interactively.

http://www.ncnr.nist.gov/staff/dimeo/panweb/pan.html

Just draw and adjust the initial curve parameters on
the data itself, then go fit it with a click of the button.
Of course, it is simply a wrapper for MPFIT. The tutorial
Rob has provided is helpful for getting started.

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/

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[Message index]

		Re: fitting mixed gaussians By: btt on Fri, 20 May 2005 07:10
		Re: fitting mixed gaussians By: Craig Markwardt on Wed, 18 May 2005 17:37
		Re: fitting mixed gaussians By: jcami on Wed, 18 May 2005 13:35
		Re: fitting mixed gaussians By: btt on Wed, 18 May 2005 07:54
		Re: fitting mixed gaussians By: Rob Dimeo on Tue, 17 May 2005 12:55
		Re: fitting mixed gaussians By: David Fanning on Tue, 17 May 2005 11:32

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