[Insight-developers] Modifying MaskImageFilter to work on VectorImage

Fri Apr 22 08:58:59 EDT 2011

Le 22 avr. 11 à 14:37, Bradley Lowekamp a écrit :

> I very much would like to get this filter working with VectorImages.
>
> I don't want this to get forgotten. I think I will be able to take a  
> stab at it based on some of Cory's work in github.
>
> The same technique should be applied to the NotMaskImageFilter as  
> well, are there other similar masking filters?

There is a masking filter for the LabelMap.

Gaëtan

>
> Brad
>
>
> On Apr 12, 2011, at 4:12 AM, Gaëtan Lehmann wrote:
>
>>
>> Le 12 avr. 11 à 07:33, Cory Quammen a écrit :
>>
>>> Hi Gaëtan,
>>>
>>> Thank you for your thoughtful comments.
>>>
>>> 2011/4/11 Gaëtan Lehmann <gaetan.lehmann at jouy.inra.fr>:
>>>>
>>>> Hi Cory,
>>>>
>>>> I think this code would fail if the mask filter is run a second
>>>> time with a
>>>> vector image with a different number of components.
>>>> There should be a check for the number of components in
>>>> BeforeThreadedGenerateData().
>>>
>>> Yes, it would be good to check that the number of components in the
>>> OutsideValue matches the number in the image, throwing an  
>>> exception if
>>> the number of components doesn't match.
>>>
>>>> The initialization of the default value of OutsideValue is quite
>>>> problematic, as it can be done only when the number of components
>>>> is known.
>>>
>>> Agreed!
>>>
>>>> A better option would be to have a way to say "I want to use the
>>>> default
>>>> value" - in that case the value can be generated in
>>>> BeforeThreadedGenerateData() and would fit the vector the filter is
>>>> currently working on - or "I want to use that value" and then it is
>>>> the
>>>> responsibility of the user to provide the right number of  
>>>> components.
>>>>
>>>> One way to implement that is to use a 3rd input for the filter
>>>> which would
>>>> be of type
>>>>
>>>> SimpleDataObjectDecorator< PixelType >
>>>>
>>>> and to not provide a default value by default - just keep the 3rd
>>>> input as
>>>> NULL. If there is no 3rd input, then the default value of
>>>> OutsideValue can
>>>> be generated in BeforeThreadedGenerateData(). If there is a 3rd
>>>> input, then
>>>> just use the value provided.
>>>
>>> While your suggestion sounds reasonable, the same behavior can  
>>> also be
>>> achieved using the current ITK norm of setting filter constants  
>>> via a
>>> method. All it would take would be to examine the OutsideValue to  
>>> see
>>> if it is zero length or if it consists of all zeros, and if so,  
>>> infer
>>> that the user wants to use the default value with the correct number
>>> of components. To get back to the "default" value, all the user  
>>> would
>>> have to do is set the OutsideValue to some vector of zeros or a
>>> zero-length vector. Does that seem reasonable?
>>>
>>>> An additional benefit of that approach: the OutsideValue can be
>>>> provided
>>>> through the pipeline, which is not the case currently.
>>>
>>> I think that your notion of treating filter constants as inputs to  
>>> the
>>> pipeline is very interesting and has merit, but I'll defer to more
>>> experienced developers to determine if that is where ITK should be
>>> heading.
>>>
>>
>> Hi Cory,
>>
>> You're right, this is not the purpose of this change.
>> Your proposition to use the default value for a zero length vector
>> seems quite good to me.
>>
>> Gaëtan
>>
>>
>>> Thanks,
>>> Cory
>>>
>>>>
>>>>
>>>> Le 11 avr. 11 à 07:30, Cory Quammen a écrit :
>>>>
>>>>> David and Luis,
>>>>>
>>>>> I have posted a potential solution on github.
>>>>>
>>>>>
>>>>> https://github.com/cquammen/ITK/commit/a92bcc79f267d79f48abb7358881c4b2323ae01d
>>>>>
>>>>> I will post it to gerrit if you don't see any showstoppers.
>>>>>
>>>>> Thanks,
>>>>> Cory
>>>>>
>>>>> On Sun, Apr 10, 2011 at 5:50 PM, Luis Ibanez <luis.ibanez at kitware.com
>>>>>>
>>>>> wrote:
>>>>>>
>>>>>> Hi David,
>>>>>>
>>>>>> We have been discussing this problem with Julien Malik from the
>>>>>> Orfeo Toolbox team.
>>>>>>
>>>>>> In summary, there is a function in the NumericTraits that is
>>>>>> intended
>>>>>> to deal with management of size in containers of variable size
>>>>>> such as the VariableLengthVector and the std::vector.
>>>>>>
>>>>>> Regarding your questions, please see below.
>>>>>>
>>>>>> On Thu, Apr 7, 2011 at 7:50 PM, David Doria
>>>>>> <daviddoria at gmail.com> wrote:
>>>>>>>
>>>>>>> We have been having some discussion on the best way to allow
>>>>>>> MaskImageFilter
>>>>>>> to work on VectorImage (with pixels of type
>>>>>>> VariableLengthVector) . The
>>>>>>> problem is that the length of a VariableLengthVector is not
>>>>>>> defined at
>>>>>>> compile time. This means that in the MaskInput functor, the
>>>>>>> member m_OutsideValue cannot be initialized.
>>>>>>>
>>>>>>> Brad has identified two problems,
>>>>>>>
>>>>>>> 1) How do we initialized the member variable in the functor?
>>>>>>>
>>>>>>
>>>>>> We usually add "Set" methods to the functor,
>>>>>> the add "Set" methods to the Filter itself,
>>>>>> and they simply call the "Set" methods of the functor.
>>>>>>
>>>>>>> This seems to be the main issue I'm not sure how to address.
>>>>>>>
>>>>>>> 2) When do we detect the size of the vector image, and use
>>>>>>> reasonable
>>>>>>> defaults?
>>>>>>>
>>>>>>
>>>>>>
>>>>>> At run time,
>>>>>> by asking them for their "GetNumberOfComponents()
>>>>>> from the vector image.
>>>>>>
>>>>>> Reasonable default (otherwise) is "1".
>>>>>>
>>>>>>> We think this could be done in BeforeThreadedGenerateData.
>>>>>>>
>>>>>>
>>>>>> Yes, that's a good place.
>>>>>>
>>>>>> The GenerateInputInformation() or
>>>>>> GenerateOutputInformation() may
>>>>>> be good places as well.
>>>>>>
>>>>>>
>>>>>>> The complete conversation is here:
>>>>>>>
>>>>>>> http://review.source.kitware.com/#change,1338
>>>>>>> Any thoughts are welcome!
>>>>>>> Thanks,
>>>>>>>
>>>>>>> David
>
> ========================================================
> Bradley Lowekamp
> Lockheed Martin Contractor for
> Office of High Performance Computing and Communications
> National Library of Medicine
> blowekamp at mail.nih.gov
>
>

-- 
Gaëtan Lehmann
Biologie du Développement et de la Reproduction
INRA de Jouy-en-Josas (France)
tel: +33 1 34 65 29 66    fax: 01 34 65 29 09
http://voxel.jouy.inra.fr  http://www.itk.org
http://www.mandriva.org  http://www.bepo.fr

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