[Insight-users] registration

[imho]

Hi Luis,

in the Software Guide there is a chapter about deformable registration 
page 229.
Won't this do what I want?

Thanks



Luis Ibanez wrote:
> 
> Hi Imho,
> 
> I'm affraid that what you are looking for, is not
> available in the toolkit at this point.
> 
> The Model to Image registration approach is not
> a Point based registration. It is not associating
> points from two point sets as ICP does.
> 
> Instead you have a geometrical model and you
> define your own metric that will measure how well
> the model match to an image.
> 
> PointSets are one among many other possible
> representations of SpatialObjects.
> 
> You may want to look at the Model Based Registration
> section of the SoftwareGuide
> 
> Section 7.14, pdf-pages 234-244.
> 
> 
> This algorithm is fitting a geometrical model to
> an image.
> 
> 
> The problem with ICP is that there is a lot of
> time spent in finding point correspondances.
> Actually most of the time goes wasted in this
> stage of the algorithm. This time grows to the
> square of the number of points unless you use
> some kind of auxiliary data structure like a
> PointLocator.
> 
> If you imagine to build an image with a distance
> map of one of the point sets, and then registering
> the other point set against this image, you will
> visualize better why Model to Image registration
> may be more efficient than Model To Model registration.
> 
> Note that the group developing this techniques is
> actually doing Liver registration for image guided
> intervention.  In this context, what you want to do
> is to create a geometrical model of the Liver, using
> the SpatialObjects available in:
> 
>             Insight/Code/SpatialObject
> 
> Then register such model against an image.
> 
> Modeling is probably the next step in the evolution
> of medical image algorithms since it allows to
> introduce anatomical meaning to the data representation.
> 
> Note that PointSets and Image are not aware of
> representing a Liver, a Hearth or a Lung. SpatialObjects
> on the other hand can be built with growing complexity
> using a CSG-kind of grouping, making possible to generate
> meaninful shapes.
> 
> 
> 
> Please let us know if you have further questions.
> 
> 
> 
> Thanks
> 
> 
>   Luis
> 
> 
> 
> ----------------------------------------
> 
> imho wrote:
> 
>> Hi Luis,
>>
>> you said that Iterative Closest Point wasn't implemented, so wich 
>> algorithm is it? Iterative Inverse Perspective? Another one?
>>
>> thanks
>> imho
>>
>> Luis Ibanez wrote:
>>
>>>
>>> Hi Imho,
>>>
>>> At this point probably the more interesting
>>> method is Model to Image registration.
>>>
>>> This is done right now in ITK by using the
>>> SpatialObject classes for representing
>>> geometrical models. An example on Model
>>> to Image registration is available in the
>>> SoftwareGuide.
>>>
>>>
>>> Does this help to answer your question ?
>>>
>>>
>>>    Luis
>>>
> 
> 
> 
>