[Insight-users] extract slice from RGB image
john smith
mkitkinsightuser at gmail.com
Fri Jul 1 05:09:21 EDT 2011
I have looked my code carefully an d I have found my mistake
typedef itk::Image< RGBPixelType, 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();
Thanks a lot
2011/7/1 john smith <mkitkinsightuser at gmail.com>
> I have made this change in my code, but still the problem remain the same
>
>
> typedef itk::Image<RGBPixelType,2> 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();
>
> 2011/7/1 Juan Vidal <juanvidalallende at gmail.com>
>
>> Ok, I guess that you just want to extract an RGB 2D slice from a 3D RGB
>> image.
>>
>> Then, your mistake is OutputPixelType. RGBPixels are vectors of unsigned
>> chars, and can't be directly converted to scalars (just unsigned chars). The
>> fastest fix could be this:
>>
>> typedef itk::Image<RGBPixelType,2> OutputPixelType_extract_RGB;
>>
>> By the way, you probably missed writer->SetFileName() in your code ;)
>>
>> HTH
>>
>>
>>
>>
>> 2011/7/1 john smith <mkitkinsightuser at gmail.com>
>>
>>> Well, to explain what I am trying to do. I have created a 3D RGB image as
>>> a result of a segmentation procedure. To create this image I had used
>>> itkLabelOverlayImageFilter.So this image was created by a greyscale image
>>> and a label image, so I get the result of the initial greyscale image and
>>> the label image with blue color. When I have tried to extract a slice from
>>> the image I got this error
>>> *error C2440: 'static_cast' : cannot convert from
>>> 'itk::RGBPixel<TComponent>' to 'unsigned char' *. I have included my
>>> code in the begining of this topic. I also cannot understand the second step
>>> very well.Why I should do something like this? What should I do for this
>>> task?
>>>
>>> Thanks for your response
>>>
>>>
>>>
>>> 2011/7/1 Juan Vidal <juanvidalallende at gmail.com>
>>>
>>>> Well, I don't know exactly what your are trying to do, but in my opinion
>>>> you could probably split your problem:
>>>>
>>>> 1) Extract the desired 2D RGB slice from the 3D RGB image
>>>> (ExtractImageFilter should work).
>>>> 2) Convert the 2D RGB slice to unsigned char
>>>>
>>>> The second point depends on the purpose of your application. You might
>>>> want to extract one of the channels, or perhaps convert the RGB image to
>>>> grayscale in some fashion...
>>>>
>>>> HTH
>>>>
>>>>
>>>>
>>>>
>>>> 2011/6/30 john smith <mkitkinsightuser at gmail.com>
>>>>
>>>>> 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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>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>> _____________________________________
>>>>> 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.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-users
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Juan Vidal Allende
>>>>
>>>
>>>
>>
>>
>> --
>> Juan Vidal Allende
>>
>
>
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