[Insight-users] Some Questions About the virtual domain in the ImageToimageMetricv4

[Champ Frédéric]

Hi Brian,

Thanks for your reponse.

I asked this question about the virtual domin because I'm trying to 
registrer a 3D volume  M, on a slice of an other 3D volume F, e.g a 3D 
image with size[2]=1
I use the Mattes Mutual Information because it's the one that gives the 
most accurate results in my case.
But, it always return an error message because I never fulfill this 
condition in itkMattesMutualInformationImageToImageMetricv4.hxx :

        /  if( this->GetNumberOfValidPoints() < numberOfPoints / 16 )
             {
             itkExceptionMacro("Too many samples map outside moving
        image buffer. There are only "
        << this->m_NumberOfValidPoints << " valid points out of "
        << numberOfPoints << " total points. The images do not
        sufficiently "
                               "overlap. They need to be initialized to
        have more overlap before this "
                               "metric will work. For instance, you can
        align the image centers by translation."
        << std::endl);
             }/

M size is 42*42*21 = 37044 points and 37044 / 16 =  2 315,25 but F size 
is only 42*42*1 = 1764 points.

With the old registration framework this registration was possible but 
not thread safe...

Is there another way to perform a slice by slice registration with the 
framework v4 ?

Thanks a lot,

Fred


Le 22/01/2013 18:33, brian avants a écrit :
> briefly, the virtual domain evaluates an image difference metric as:
>
>      J - fixed image
>
>      K - moving image
>
>      x - a point in the virtual domain
>
>      \|   J (  T_fixed( x )  )   -   K ( T_moving(x) ) \|^2
>
>   By default T_fixed( x ) is the identity and T_moving is what you
> optimize.  Other metrics are implemented in the same way.
>
> This lets the user :
>
>   1 ) control the resolution @ which registration is performed ... e.g.
> to implement multi-resolution approaches by setting the virtual domain
> to be smaller than the domain of J.
>
>   2 )  allows the fixed image to have a transform as well.   for
> instance, when the image registration is performed in an unbiased
> space.
>
> This also lets one minimize the number of interpolation / downsampling
> operations.
>
> brian
>
>
>
>
> On Tue, Jan 22, 2013 at 5:02 AM, Champ Frédéric<champ at unistra.fr>  wrote:
>    
>> Hi,
>>
>> For a 3D registrations with the framework v4:
>>
>> - What exactly does the virtual domain ?
>> - Does it necessary to specify it if the moving and fixed regions are
>> different ?
>>
>> Fred
>>
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