[Insight-users] Continuous Index

[Luis Ibanez]

Hi Xiang,

If you need to evaluat the image at ContinousIndex positions,
or at Point positions you will need to use an Interpolator.

Something like

   interpolator->SetImage( image );
   interpolator->Evaluate( point );
   interpolator->Evaluate( continuousIndex );

For a list of ITK Interpolators, please look at:
http://public.kitware.com/Insight/Doxygen/html/group__ImageInterpolators.html


Note however, that, depending on how you track
fibers, what you may actually need is to compute
features at those points (or continuous indices)
and therefore you may have to use ImageFunctions
there.

For example:

itkGaussianBlurImageFunction.h
itkGaussianDerivativeImageFunction.h



       Regards,


                Luis



----------------------------------------------------------------------
On Tue, Jun 30, 2009 at 1:22 PM, Xiang Hao <haoxiang at yahoo.cn> wrote:

> Hi Luis,
>
> Thank you so much, Luis. I will try it, and BTW, as I remember, there is a
> problem about setPixel() and getPixel() method while I am using the
> ContinuousIndex. It said it cannot find the corresponding method. Anyway, I
> will try your method and try to make it work.
>
> Thank you again,
> Xiang
>
>
> On Tue, Jun 30, 2009 at 10:29 AM, Luis Ibanez <luis.ibanez at kitware.com>wrote:
>
>>
>>
>> Hi Xian,
>>
>> If you need sub-pixel locations for the points of the fibers,
>> yes, it makes sense to use ContinuousIndex instead of
>> Indexes for representing the location of fibers centers.
>>
>> That said, it may be preferable to use itk::Point<> since
>> that will take into account also the pixel spacing, image
>> origin, and image orientation, and you will be able to
>> do things like overlapping a visualization of the fibers
>> with the original image.
>>
>> A) If you need to convert Index to ContinousIndex you
>>      can use the method:
>>
>>     Constructor
>>
>>      IndexType  index;
>>      ContinuousIndexType  cindex( index );
>>
>> B) In order to convert Continuous index to Index you
>>      can use the method CopyWithRound()
>>
>>     index.CopyWithRound( continousIndex )
>>
>> C) In order to convert an index into a physical point
>>      and back you can use the image methods
>>
>>       TransformIndexToPhysicalPoint( index, point );
>>       TransformPhysicalPointToIndex(point, index );
>>
>>
>>
>>   Regards,
>>
>>
>>
>>         Luis
>>
>>
>>
>>
>> ----------------------------------------------------------------------------------------------
>> On Sun, Jun 28, 2009 at 2:42 PM, Xiang Hao <haoxiang at yahoo.cn> wrote:
>>
>>> Hi,
>>>
>>> I am trying to write a tractography program.
>>> Now I use discrete index:
>>>
>>> Dimension =3;
>>> typedef int OutputPixelType;
>>> typedef itk::Image< OutputPixelType, Dimension > OutputImageType;
>>> OutputImageType::IndexType pixelIndex;
>>>
>>> So now the pixelIndex is discrete index and I want to change it to
>>> continuous index. I know there is an ContinuousIndex class in ITK. I wonder
>>> whether I should use this class and how to use it in order to change the
>>> index to continuous index.
>>>
>>>
>>> --
>>> Cheers,
>>> Xiang
>>>
>>>
>>> --
>>> Cheers,
>>> Xiang
>>>
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>>
>
>
> --
> Cheers,
> Xiang
>
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