[Insight-developers] VectorImage: and contiguous memory assumption

[Luis Ibanez]

Hi Brian,


The memory layout of the image type

         itk::Image< Vector , Dimension >

for

          Vector = itk::Vector< float, 2 >

is:

      x1 y1 x2 y2 x3 y3 x4 y4.... xN yN


Where N is the number of pixels.


So,
the components of a pixel are grouped
contiguously in memory.


      Luis


--------------------------
On Tue, Mar 29, 2011 at 4:09 PM, brian avants <stnava at gmail.com> wrote:
> luis
>
> do you by chance know the memory layout for the
>
> itk::Image< Vector , type >  ?
>
> is it
>
> x1 x2 x3 y1 y2 y3
>
> or
>
> x1 y1 x2 y2 x3 y3
>
> ?
>
> brian
>
>
>
>
> On Wed, Mar 23, 2011 at 8:49 PM, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>> Brad, Nick,
>>
>> It turned out that I was wrong about the internal
>> memory organization of the VectorImage class.
>>
>> Looking closely at the code, particularly the
>> GetPixel, SetPixel methods of this class,
>> and after checking with Karthik (who actually
>> implemented this class), it turns out that the
>> memory organization is actually
>>
>>
>> 1) All the components of pixel 1, followed by
>> 2) All the components of pixel 2, followed by
>> 3) All the components of pixel 3, followed by
>> 4) All the components of pixel 4, followed by
>>
>> and so on...
>>
>>
>> Instead of what I wrongly thought:
>>
>>
>> 1) All the pixels of component 1, followed by
>> 2) All the pixels of component 2, followed by
>> 3) All the pixels of component 3, followed by
>>
>> and so on...
>>
>>
>>
>> So, it makes me wonder if there is a case
>> to be made for introducing an image class
>> with the second type of memory organization...
>>
>>
>>     Luis
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Kitware offers ITK Training Courses, for more information visit:
>> http://kitware.com/products/protraining.html
>>
>> Please keep messages on-topic and check the ITK FAQ at:
>> http://www.itk.org/Wiki/ITK_FAQ
>>
>> Follow this link to subscribe/unsubscribe:
>> http://www.itk.org/mailman/listinfo/insight-developers
>>
>