[Insight-users] extract slice from RGB image

[john smith]

Could somebody explain in some words what must be done in order to extract a
2D slice from a RGB 3D image? I am trying to find an example (but I didn't
find anything) and I am reading the docs but I am totally lost. This task
may be very easy but I really need some help.
Any response would be very useful.

Thanks in advace

2011/6/30 john smith <mkitkinsightuser at gmail.com>

> You may have right as it should work properly.It is the first time I am
> working with RGB images. But what changes should be done?
>
> Thanks for yoyr response
>
>
> 2011/6/30 robert tamburo <robert.tamburo at gmail.com>
>
>> Do you really expect the filter to extract a 2D image of unsigned char
>> pixels from a 3D image of RGB pixels?
>>
>> On Thu, Jun 30, 2011 at 3:07 PM, john smith <mkitkinsightuser at gmail.com>wrote:
>>
>>> Hello to all,
>>>
>>> I am trying to read an RGB image, then use the ExtractImageFilter and
>>> finally, write the RGB slice. I have written the following code, but I get
>>> this error
>>> *error C2440: 'static_cast' : cannot convert from
>>> 'itk::RGBPixel<TComponent>' to 'unsigned char' *. Do you know what I am
>>> doing wrong?
>>>
>>> Thanks in advance
>>>
>>> ///////// code //////////////
>>> typedef itk::RGBPixel<unsigned char> RGBPixelType;
>>>   typedef itk::Image<RGBPixelType,3> RGBImageType;
>>>
>>>    typedef  itk::ImageFileReader< RGBImageType > ReaderType_RGB;
>>>
>>>      ReaderType_RGB::Pointer reader_RGB = ReaderType_RGB::New();
>>>
>>>      reader_RGB->SetFileName( "output.hdr"  );
>>>      reader_RGB->Update();
>>>
>>>
>>>   typedef unsigned char       OutputPixelType_extract_RGB;
>>>   typedef itk::Image< OutputPixelType_extract_RGB, 2 >
>>> OutputImageType_extract_RGB;
>>>    typedef itk::ExtractImageFilter< RGBImageType,
>>> OutputImageType_extract_RGB > FilterType_extract_RGB;
>>>     FilterType_extract_RGB::Pointer filter_extract_RGB =
>>> FilterType_extract_RGB::New();
>>>
>>>   RGBImageType::RegionType inputRegion =
>>>           reader_RGB->GetOutput()->GetLargestPossibleRegion();
>>>
>>>
>>>   RGBImageType::SizeType size = inputRegion.GetSize();
>>>
>>>   // get the size of the hole 3D image
>>>   size_x = size[0];
>>>   size_y = size[1];
>>>    size_z = size[2];
>>>
>>>   // get slices of z coordiante
>>>   size[2] = 0;
>>>
>>>    RGBImageType::IndexType start = inputRegion.GetIndex();
>>>   ui->verticalScrollBar_z->setRange(0,size_z-1);
>>>   unsigned int sliceNumber = ui->verticalScrollBar_z->value();
>>>   start[2] = 10;
>>>
>>>
>>>   RGBImageType::RegionType desiredRegion;
>>>   desiredRegion.SetSize( size );
>>>   desiredRegion.SetIndex( start );
>>>
>>>   filter_extract_RGB->SetExtractionRegion( desiredRegion );
>>>
>>>     typedef  itk::ImageFileWriter< OutputImageType_extract_RGB  >
>>> WriterType_RGB;
>>>      WriterType_RGB::Pointer writer_RGB = WriterType_RGB::New();
>>>     writer_RGB->SetFileName( "z.png" );
>>>
>>>    filter_extract_RGB->SetInput( reader_RGB->GetOutput() );
>>>    writer_RGB->SetInput( filter_extract_RGB->GetOutput() );
>>>
>>>     try
>>>     {
>>>     writer_RGB->Update();
>>>     }
>>>   catch( itk::ExceptionObject & err )
>>>     {
>>>     std::cerr << "ExceptionObject caught !" << std::endl;
>>>     std::cerr << err << std::endl;
>>>     }
>>>
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>>
>
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