[IGSTK-Developers] Registration error computation

[Andinet Enquobahrie]

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