[Insight-users] MattesMutualInformationImageToImageMetric exception thrown

[Luis Ibanez]

Hi Rick,

This exception is thrown when the Transform is so way off that the
Moving image is no longer mapped on top of the Fixed image. In other
words, the two images do not have any overlap.

It typically occurs if you have a poor initialization of the transform
parameters, or if you have set the parameters of your optimizer to move
too fast. For example:

a Learning Rate too large in the Gradient Descent Optimizer
a Step length too large in the Regular Step Gradient Descent Optimizer
a Radius too large in the One Plus One Evolutionary optimizer


It also may happen when you have inappropriate scaling values for
the parameters passed to the optimizer. For example if your rotations
(in radians) are being performed at the numerical range of your
translations (in millimeters).

Are you plugging a Command/Observer to the optimizer ?

Looking at the trace of values provided by the command observer
is a good way of finding which one of the following conditions
are the cause of this exception being thrown.


     Regards,


        Luis



======================
Rick Shilling wrote:
> Hi-
> 
> I'm getting an exception thrown on:
> 
> typedef itk::ImageRegistrationMethod<ImageType,ImageType > 
> RegistrationType; 
> RegistrationType::Pointer registration  = RegistrationType::New();
> .
> .
> .
> registration->StartRegistration();
> EOF
> 
> itk::ExceptionObject (00F58FA8)
> Location: "Unknown"
> File: 
> C:\InsightToolkit-2.2.0\Code\Algorithms\itkMutualInformationImageToImageMetric.txx 
> Line: 193
> Description: itk::ERROR: MutualInformationImageToImageMetric(0157D530): 
> All the sampled point mapped to outside of the moving image
> 
> Does anyone know what needs to be checked or setup to ensure the sampled 
> points are within the itk image?  Note that I am using a subregion of 
> the itk fixedImage in the registration process & not just a subset of 
> the number of spatial samples.  Thanks.
> 
> -Rick
> 

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