[ITK Community] [Insight-users] Filters Input Image Pixel Type

[elena bresciani]

Ok ok, I get it! :)

Thank you very much

Cheers,
Elena



2013/12/12 Mauro Maiorca <mauromaiorca at gmail.com>

> On Thu, Dec 12, 2013 at 9:06 PM, elena bresciani <
> elena.bresciani87 at gmail.com> wrote:
>
>> > Ok, thanks but my question was more like How can I know which input
> image type requires a particular filter?
>
> ah okay! Any descent of ImageToImageFilter it is meant to support at least
> all the native types such as float, char, int, and so on. As all the
> classes are templated, so the numeric types are those compatible with your
> C++ compiler. However, when you write an image on a file you are restricted
> on the data types supported by the image format you are using, for example
> MRCImageIO complains with scalar double types, while double type
> works perfectly fine with MetaIO format.
>
> > For example: itk::GradientMagnitudeImageFilter requires the input image
> to have a float pixel type (as described in the software guide).
> > Where can I find this kind of informations?
>
> In the case of itk::GradientMagnitudeImageFilter you might want to have a
> floating point pixel values, as you might want a continuous histogram, i.e.
> you don't want to approximate real values to an integer type, as you loose
> all the decimals. But itk::GradientMagnitudeImageFilter works perfectly
> fine with integers too. Another example, if you want to threshold an image,
> it's unnecessary to use a floating point pixel type, as usually you need to
> store integer values, not decimals. But it works perfectly fine using
> floating pixel types. It really depends on what is the problem you are
> going to solve. Does it make sense?
>
> cheers,
> Mauro
>
>
>
>
>
> 2013/12/12 Mauro Maiorca <mauromaiorca at gmail.com>
>>
>>> Hi Elena,
>>>
>>> have a look at the ITK software guide (
>>> http://www.itk.org/ItkSoftwareGuide.pdf), chapter 4 (User's guide ->
>>> Data Representation -> Image), it might answer your question.
>>>
>>> Section 4.1.1 shows how to create a 3D image with unsigned short pixel
>>> data, in summary you have to define your image type as:
>>> typedef itk::Image< unsigned short, 3 > ImageType;
>>> If you want to create an image with unsigned int pixel data, you have to
>>> replace "unsigned short" with "unsigned int", i.e.
>>> typedef itk::Image< unsigned int, 3 > ImageType;
>>>
>>> You can play with the examples that you can find either in your ITK
>>> source directory (Examples/DataRepresentation/Image/Image1.cxx, etc etc) or
>>> online (
>>> https://github.com/Kitware/ITK/blob/master/Examples/DataRepresentation/Image/Image1.cxxetc etc)
>>>
>>> If you want to cast image types (for example converting from unsigned
>>> short to unsigned int), have a look at section "6.3 Casting and Intensity
>>> Mapping" of the ITK software guide.
>>>
>>> Hope it helps.
>>>
>>> cheers,
>>> Mauro
>>>
>>>
>>>
>>>
>>>
>>> On Thu, Dec 12, 2013 at 8:19 PM, elena bresciani <
>>> elena.bresciani87 at gmail.com> wrote:
>>>
>>>> Hi to everybody,
>>>>
>>>> I have a (probably really silly) question about which kind of input
>>>> image pixel type does a filter require.
>>>> Is it wrote in the doxygen documentation? If yes, where?
>>>>
>>>> I'm obviously a beginner and I can't understand well how to read the
>>>> documentation...
>>>>
>>>> Thank you in advance,
>>>>
>>>> Elena
>>>>
>>>>
>>>>
>>>> _____________________________________
>>>> 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://www.kitware.com/products/protraining.php
>>>>
>>>> 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-users
>>>>
>>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/community/attachments/20131212/cb3bb196/attachment.html>
-------------- next part --------------
_____________________________________
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://www.kitware.com/products/protraining.php

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-users