[Insight-users] Cost function value over a region

[Martin Kavec]

Hi Luis,

On Mon, 20 Dec 2004, Luis Ibanez wrote:

>
> Hi Martin,
>
>
> Some questions:
>
>
> A)  What "GetNumberOfPixels()" method are you exactly calling ?
>      I don't think there is a method with this name on the
>      Image metrics...

Sorry, I didn't have very good Internet connection at a time of writing to
check exactly the name of function. I used virtual function called
"GetNumberOfPixelsCounted"

http://www.itk.org/Doxygen/html/classitk_1_1ImageToImageMetric.html#a9

>
>
> B)  The number of samples used shouldn't be the full number
>      of pixels in the image. That will be a killer for the
>      performance of the metric. The number of samples should
>      be in the range of 2%-10% of the total number of pixels.
>
>
> C)  What specific implementation of Mutual Information are you using ?
>      There are 4 of them in ITK:
>
>         - Viola & Wells
>         - Mattes
>         - KullbackLiebler
>         - NormalizedMutualInformation

I use NormalizedMutualInformation.

>
> http://www.itk.org/Insight/Doxygen/html/group__RegistrationMetrics.html
>
>
>
>
> Please let us know,
>
>
>
>    Thanks
>
>
>
>       Luis

Cheers,

Martin