[IGSTK-Developers] Registration error computation

[Stephen R. Aylward]

What amount having more than one error quantity.   Perhaps 
ExpectedErrorValue and MaxErrorvalue member variables in the igstkTransform?

I suggest this because, as I recall and please correct me if I am wrong, 
the work by West (TRE) assumes a rigid (or affine?) transform.   We need 
to plan for future deformable registration methods.   All can be reduced 
to a TRE value, but the distribution of that value changes as a function 
of the transform.  So, reporting expected and maximum values gives the 
critical numbers needed for patient safety.

Stephen

Andinet Enquobahrie wrote:
> Hi Folks,
> 
> I would like to get your opinion on how to integrate a registration 
> error computation scheme into igstk.   The goal is to determine the 
> accuracy of a target registration using transform parameters computed by 
> "igstkLandmarkRegistration". From West et al. paper,  target 
> registration error  (TRE) is a function of  landmark registration error 
> and the location of the target with respect to the landmarks (distance 
> from the target to the three principal axis of the landmark 
> configuration).   Integration of this computation into igstk is a bit 
> tricky since it is  "target" and "target location" specific.
> 
> To implement this computation in igstk, I see the need for the following
> 
> 1) A member variable  to store landmark configuration information in 
> "igstkTransform"  (This could probably be just a three by three matrix 
> to encode the principal axis of the landmarks configuration)
> 2) Set/Get methods in "igstkTransform" for  this new member variable.
> 3) ComputeTargetRegistrationError()  method to compute the error. This 
> method will use the location of the target and landmark configuration 
> information to compute the registration error. The computed registration 
> error could be stored in the "ErrorValue" igstkTransform member 
> variable. However, I am not sure which class this method would perfectly 
> fit in . Either in Tracker class where target transformation is reported 
> to the spatial object or  in spatialobject class itself or in a new 
> helper class...
> 
> Any thoughts?
> 
> Thank you
> 
> -Andinet
> 
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-- 
=============================================================
Stephen R. Aylward, Ph.D.
Chief Medical Scientist
Kitware, Inc.
http://www.kitware.com