[Insight-users] Statistics: Find out coefficient of affine transform

[Luis Ibanez]

Hi Mathieu,

You may want to try the KalmanLinearEstimator.

http://www.itk.org/Insight/Doxygen/html/classitk_1_1KalmanLinearEstimator.html


Your estimator will be the vector [a,b],

and your measures will be the vector [1,Y]


The Kalman Linear Estimator should converge to the vector [a,b] that
minimizes the sum of squared errors between X and (a+bY).

For an example, you may want to look at:



     Insight/Testing/Code/Algorithms/
          itkKalmanLinearEstimatorTest.cxx



    Regards,


        Luis


---------------------------
Mathieu Malaterre wrote:
> Hello,
> 
>  I have a pretty simple problem to solve and I was wondering if I
> could reuse any brick already existing in ITK.
> 
>  I am working with a 4D dataset (x,y,y and theta), where I can
> express for each pixel that:
> 
> I(x,y,z)/sin(theta) = F(x,y,z) + b*I(x,y,z)/tan(theta)
> 
>  My goal here is to find out the b constant, I do not need the
> F(x,y,z) part. Obvisouly all I need to do is draw the line
> 
>   X = a + b Y
> 
> where X = I(x,y,z)/sin(theta) and Y = I(x,y,z)/tan(theta) and the
> slope will give me 'b'.
> 
> Any suggestions on which class to reuse ?
> thanks !