[Insight-users] finding the type of an image

[john smith]

Thanks a lot,

It was exactly what I was looking!

2011/7/1 Vincent Garcia <vincent.garcia at inria.fr>

> Hi John,
>
> I'd say that reading images in ITK is not the most intuitive way to do it
> if you care to keep the original type.
> So, what I do is the following.
> I have written this function that reads only the header of the image :
>
> -------------------------------------------------------------------------
> itk::ImageIOBase::Pointer
> readImageInformation( std::string fileName )
> {
>
>     // Define image IO
>     itk::ImageIOBase::Pointer imageIO  =
> itk::ImageIOFactory::CreateImageIO( fileName.c_str(),
> itk::ImageIOFactory::ReadMode );
>
>     // Test if image exists
>     if ( !imageIO )
>         throw std::runtime_error( "Could not read image " + fileName + "."
> );
>
>     // Read image information
>     try
>     {
>         imageIO->SetFileName( fileName );
>         imageIO->ReadImageInformation();
>     }
>     catch( itk::ExceptionObject& )
>     {
>         throw std::runtime_error( "Could not read image information." );
>     }
>     return imageIO;
> }
> ------------------------------------------------------------
>
> The output of this function if an itk::ImageIOBase.
> Then, you can figure out what is the type of your image by using theses
> function on the ImageIOBase pointer :
>
> image_base->GetPixelType()
> image_base->GetComponentType()
>
> The first one tells you if your image is scalar, RGB, vector, etc. (see
> http://www.itk.org/Doxygen320/html/classitk_1_1ImageIOBase.html#abd189f096c2a1b3ea559bc3e4849f658
> ).
> The second one tells you the type of each component : short, int, double,
> etc. (see
> http://www.itk.org/Doxygen320/html/classitk_1_1ImageIOBase.html#a8dc783055a0af6f0a5a26cb080feb178
> )
>
> Like that, you can have everything you need to correctly read your image
> (dimension etc.).
> Read the class, it's pretty clear.
>
> Then, when you know the type of the input image, you use the correct
> ImageFileReader (I mean the correct templates).
> Basically, it will be a BIG switch... (thanks to templates)
>
> Cheers,
>
> Vincent Garcia
>
> ------------------------------
>
> *From: *"john smith" <mkitkinsightuser at gmail.com>
> *To: *insight-users at itk.org
> *Sent: *Friday, 1 July, 2011 11:39:07 AM
> *Subject: *[Insight-users] finding the type of an image
>
>
> I want somehow to find the type of an image. To be more specific, I have a
> greyscale and an RGB image and I want to process this two images. But when I
> load the image I do not know the type of the reader that I must use. Must I
> use an RGB pointer or a greyscale pointer?
> I hope somebody could help me to solve this problem
>
> Thanks in advance
>
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