[Trilinos-Users] Model-fitting applications in trilinos

[Ali -]

Ross,

Thanks for refering me to DAKOTA. I am trying to carry out model-based segmentation image processing using optimisation approches. As an example, assume an image involving randomly distributed Gaussian intensities, or something like this:

http://piv.vsj.or.jp/piv/data/01/piv01_1.bmp .

The aim is to detect all the Gaussian objects in the image by fitting them to a 2D Gaussian model which has 4 parameters: (x, y, sigma, I) with x and y being the centre, sigma being the deviation and I being the peak intensity. Typically each image includes a few hundereds of these little Gaussian objects, multiplied by the 4 parameters, we are dealing with over 1e+3 parameters in total.

Normally people solve this problem by segmenting the individual object (eg using watershed algorithm) and then fit them one by one using Levenberg-Marquadt method. But I was wondering, while the Trilinos solvers can handle millions of unknown in a typical PDE problem solved by FEM, why shouldn't it be possible to fit 'all' of the objects at once to a model which is simply a linear superposition of the individual models?


-Ali


Subject: RE: [Trilinos-Users] Model-fitting applications in trilinos
Date: Mon, 28 Jan 2008 13:35:27 -0700
From: rabartl at sandia.gov
To: saveez at hotmail.com; trilinos-users at software.sandia.gov










Ali,
 
Depending on what you need there are a few possibilities.  
Without knowing the details, I would recommend that you first look at a 
related project called Dakota which as parameter estimation and least-squares 
fitting methods.  You can find more information at:
 
    http://www.cs.sandia.gov/DAKOTA/software.html
 
If you only need to fit a smaller 
number of parameters, I would definitely look at Dakota first.  Fitting a 
large number of parameters (i.e. 1e+3 and up) is a lot of work to set up and 
requires some serious optimization algorithms.
 
Cheers,
 
Ross




From: trilinos-users-bounces at software.sandia.gov 
[mailto:trilinos-users-bounces at software.sandia.gov] On Behalf Of Ali 
-
Sent: Monday, January 28, 2008 12:19 PM
To: 
trilinos-users at software.sandia.gov
Subject: [Trilinos-Users] 
Model-fitting applications in trilinos



Hi,

Is there any packages in Trilinos (or 
other Sandia software) specifically designed for model-fitting 
(curve-fitting)?


-Ali



Messenger on the move. Text MSN to 63463 now! 

_________________________________________________________________
Telly addicts unite!
http://www.searchgamesbox.com/tvtown.shtml
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://software.sandia.gov/mailman/private/trilinos-users/attachments/20080128/56a62bff/attachment.html