[Insight-users] singleValuedCostFunction vs MultiValuedCostFunction

[bertrand]

Hi Julien,

Thanks for your reply.
I think I will use the same optimizer for the two functions and minimize 
the sum of these functions and write you again again if I have further 
questions.

regards,
Bertrand

Julien Jomier wrote:

> Hi Bertrand,
>
> The main difference between the SingleValuedCostFunction and the 
> MultiValuedCostFunction is the type of the measure the cost function 
> is returning.
> For a SingleValuedCostFunction only one measure is returned (and 
> optimized). For a MultiValuedCostFunction an array of measures is 
> returned.
>
> The choice of the cost function really depends on the type of 
> optimizer your are using. For instance, Levenberg-Marquardt optimizer 
> is expecting multiple values and GradiendDescent single value.
>
> > I would like two kind of cost functions in a registration process.
>
> Are you going to optimize the two cost functions at the same time? 
> meaning are you trying to minimize the sum of the cost functions? or 
> do you want to use different optimizers for each of the cost functions?
>
> If you want to use only one optimizer, the best way is to write your 
> own metric and return a value which combines the energy and the 
> regularization term. Your can derive your metric from 
> itkPointSetToImageMetric and add a function to add another image or 
> you can derive from ImageToImageMetric and add a function to add a 
> PointSet.
>
> regards,
>
> Julien
>
> bertrand wrote:
>
>> hi all
>>
>> I would like two kind of cost functions in a registration process.
>> The first one is used as a data driven energy term ( for example an 
>> itkImageToImageMetric) .
>> The second one could be considered as  a regularization  data term ( 
>> for exmaple an itkPointSetToImageMetric) .
>>
>> || So my problem is to use two CostFunction in the same registration 
>> process.
>> What is the main difference between SingleValuedCostFunction and 
>> MultiValuedCostFunction.
>> Is it a good way to resolve my problem by writing a more complex 
>> CostFunction which can take into account a lot of 
>> SingleValuedCostFunction ?
>>
>> regards,
>>
>> Bertrand
>>  
>>
>>
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