[Insight-users] how to get the buffer data

Ali Habib ali.mahmoud.habib at gmail.com
Wed Dec 29 07:58:49 EST 2010


I got it ,

but may I ask a question what's  the difference between  bitsPerComponent,
and
bitsPerPixel
I just get confused

Best regards


On Wed, Dec 29, 2010 at 4:16 PM, Dan Mueller <dan.muel at gmail.com> wrote:

> Hi Ali,
>
> Option 1:
> ImageType::Pointer image_1 = reader->GetOutput();
> unsigned int numComponents = image_1->GetNumberOfComponentsPerPixel();
> // NOTE: Only really works for itk::Vector images eg. RGBPixel returns 1
>
> Option 2:
> ImageType::Pointer image_1 = reader->GetOutput();
> InputImageType::IndexType index;
> index[0]=1;
> index[1]=1;
> ImageType::PixelType pixel_value= image_1->GetPixel( index );
> unsigned int numComponents =
>
> itk::VectorPixelTraits<ImageType::PixelType>::GetNumberOfComponents(pixel_value);
> // NOTE: This works for many image types. eg.
> // unsigned char returns 1
> // RGB returns 3
> // FixedArray<float, 4> returns 4
>
> HTH
>
> Cheers, Dan
>
> On 29 December 2010 11:17, Ali Habib <ali.mahmoud.habib at gmail.com> wrote:
> > Sorry for disturbance,
> > but I have
> > ImageType::Pointer image_1 = reader->GetOutput() ;
> > I misunderstand how to get the pixel type of  image_1 , using the 2
> options
> > you gave me . could u give me more details
> > Best regards
> >
> > On Tue, Dec 28, 2010 at 11:26 AM, Dan Mueller <dan.muel at gmail.com>
> wrote:
> >>
> >> Hi Ali,
> >>
> >> Try the following to get the image buffer as a pointer:
> >>    InputPixelType* buffer = image_1->GetBufferPointer();
> >>
> >> You can then treat the buffer as a simple pointer (e.g. cast to
> >> unsigned char *, whatever).
> >>
> >> Determining if the pixel type is scalar or not is a little trickier.
> >> At first glance the method
> >> itk::ImageBase::GetNumberOfComponentsPerPixel() seems helpful, but it
> >> does not work as you might expect (see documentation). I'm not sure if
> >> there is a better way, but I use a specialized traits class to help
> >> (see below). You use the class as follows:
> >>    InputPixelType pixel;
> >>    unsigned int numComponents =
> >> itk::VectorPixelTraits<InputPixelType>::GetNumberOfComponents(pixel);
> >>
> >> HTH
> >>
> >> Cheers, Dan
> >>
> >>
> >>
> /*=========================================================================
> >>
> >>  Program:   Insight Segmentation & Registration Toolkit
> >>  Module:    $RCSfile: itkVectorPixelTraits.h,v $
> >>  Language:  C++
> >>  Date:      $Date$
> >>  Version:   $Revision$
> >>
> >>  Copyright (c) Insight Software Consortium. All rights reserved.
> >>  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for
> >> details.
> >>
> >>     This software is distributed WITHOUT ANY WARRANTY; without even
> >>     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
> >>     PURPOSE.  See the above copyright notices for more information.
> >>
> >>
> >>
> =========================================================================*/
> >> #ifndef __itkVectorPixelTraits_h
> >> #define __itkVectorPixelTraits_h
> >>
> >> #include "itkMacro.h"
> >> #include "itkArray.h"
> >> #include "itkVector.h"
> >> #include "itkFixedArray.h"
> >> #include "itkRGBPixel.h"
> >> #include "itkRGBAPixel.h"
> >> #include "itkVariableLengthVector.h"
> >> #include "itkNumericTraits.h"
> >>
> >> namespace itk
> >> {
> >>
> >> /** \class VectorPixelTraits
> >>  * \brief Define additional traits for vector pixels (eg. fixed array,
> >> RGB).
> >>  *
> >>  * VectorPixelTraits is used to extend the traits associated with vector
> >> pixel
> >>  * types such as fixed array, RGBPixel, VariableLengthVector, and so on.
> >>  * These traits also support scalar types (such as unsigned char, short)
> >>  * so that both vector and scalar types can be treated in a unified way.
> >>  *
> >>  * Note this default implementation defines traits for all scalar types
> >>  * (eg. unsigned char, short, double, etc).
> >>  *
> >>  * \ingroup DataRepresentation
> >>  */
> >> template <class T>
> >> class VectorPixelTraits {
> >> public:
> >>  /** Get the number of components for the given type.
> >>    * An input is required for variable length types whose
> >>    * length is defined at run-time rather than compile-time.
> >>    * For other types the input is simply ignored. */
> >>  static unsigned int GetNumberOfComponents( T input ) { return 1; }
> >>
> >>  /* Return the reference to the given indexed element in the vector. */
> >>  static T *GetElement( unsigned int i, T *pixel ) { return pixel; }
> >>
> >>  /* Set the value of the left element with the value of the right. */
> >>  static void SetElement( unsigned int i, T &left, T right ) { left =
> >> right; }
> >>
> >>  /* Return the zero value. */
> >>  static T ZeroValue( T input ) { return NumericTraits<T>::ZeroValue(); }
> >>
> >>  /* Convert the given double to the pixel type.
> >>     NOTE: This is not implemented for VariableLengthVectors! */
> >>  static T Convert( double input ) { return static_cast<T>(input); }
> >> };
> >>
> >> /** Define a macro to be used for RGB types. */
> >> #define RGBSTATICTRAITSMACRO( T, E ) \
> >> template<> \
> >> class VectorPixelTraits< T<E> > { \
> >> public: \
> >>  static unsigned int GetNumberOfComponents( T<E> input ) \
> >>    { return 3; } \
> >>  static E *GetElement( unsigned int i, T<E> *pixel ) \
> >>    { return &((*pixel)[i]); } \
> >>  static void SetElement( unsigned int i, T<E> &left, T<E> right ) \
> >>    { left[i] = right[i]; } \
> >>  static T<E> ZeroValue( T<E> input ) \
> >>    { return NumericTraits<T<E>>::ZeroValue(); } \
> >>  static T<E> Convert( double input ) \
> >>    { T<E> value( static_cast<E>(input) ); return value; } \
> >> }; \
> >>
> >> RGBSTATICTRAITSMACRO( RGBPixel, unsigned char );
> >> RGBSTATICTRAITSMACRO( RGBPixel, signed char );
> >> RGBSTATICTRAITSMACRO( RGBPixel, unsigned short );
> >> RGBSTATICTRAITSMACRO( RGBPixel, signed short );
> >> RGBSTATICTRAITSMACRO( RGBPixel, unsigned long );
> >> RGBSTATICTRAITSMACRO( RGBPixel, signed long );
> >> RGBSTATICTRAITSMACRO( RGBPixel, float );
> >> RGBSTATICTRAITSMACRO( RGBPixel, double );
> >>
> >> /** Define a macro to be used for RGBA types. */
> >> #define RGBASTATICTRAITSMACRO( T, E ) \
> >> template<> \
> >> class VectorPixelTraits< T<E> > { \
> >> public: \
> >>  static unsigned int GetNumberOfComponents( T<E> input ) { return 4; } \
> >>  static E *GetElement( unsigned int i, T<E> *pixel ) { return
> >> &((*pixel)[i]); } \
> >>  static void SetElement( unsigned int i, T<E> &left, T<E> right ) {
> >> left[i] = right[i]; } \
> >>  static T<E> ZeroValue( T<E> input ) { T<E> zero =
> >> NumericTraits<T<E>>::ZeroValue(); zero.SetAlpha( 254 ); return zero; }
> >> \
> >>  static T<E> Convert( double input ) { T<E> value(
> >> static_cast<E>(input) ); return value; } \
> >> }; \
> >>
> >> RGBASTATICTRAITSMACRO( RGBAPixel, unsigned char );
> >> RGBASTATICTRAITSMACRO( RGBAPixel, signed char );
> >> RGBASTATICTRAITSMACRO( RGBAPixel, unsigned short );
> >> RGBASTATICTRAITSMACRO( RGBAPixel, signed short );
> >> RGBASTATICTRAITSMACRO( RGBAPixel, unsigned long );
> >> RGBASTATICTRAITSMACRO( RGBAPixel, signed long );
> >> RGBASTATICTRAITSMACRO( RGBAPixel, float );
> >> RGBASTATICTRAITSMACRO( RGBAPixel, double );
> >>
> >> /** Define a macro to be used for all (fixed) array types. */
> >> #define FIXEDARRAYSTATICTRAITSMACRO( T, E, N ) \
> >> template<> \
> >> class VectorPixelTraits< T<E,N> > { \
> >> public: \
> >>  static unsigned int GetNumberOfComponents(T<E,N> input) { return N; } \
> >>  static E *GetElement( unsigned int i, T<E,N> *pixel) { return
> >> &((*pixel)[i]); } \
> >>  static void SetElement( unsigned int i, T<E,N> &left, T<E,N> right)
> >> { left[i] = right[i]; } \
> >>  static T<E,N> ZeroValue( T<E,N> input ) { T<E,N> zero; zero.Fill(
> >> NumericTraits<E>::ZeroValue() ); return zero; } \
> >>  static T<E,N> Convert( double input ) { T<E,N> value; value.Fill(
> >> static_cast<E>(input) ); return value; } \
> >> }; \
> >>
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned char, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed char, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned short, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed short, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned long, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed long, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, float, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, double, 1 );
> >>
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned char, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed char, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned short, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed short, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned long, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed long, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, float, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, double, 2 );
> >>
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned char, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed char, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned short, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed short, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned long, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed long, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, float, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, double, 3 );
> >>
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned char, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed char, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned short, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed short, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, unsigned long, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, signed long, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, float, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( FixedArray, double, 4 );
> >>
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned char, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed char, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned short, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed short, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned long, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed long, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, float, 1 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, double, 1 );
> >>
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned char, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed char, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned short, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed short, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned long, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed long, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, float, 2 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, double, 2 );
> >>
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned char, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed char, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned short, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed short, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned long, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed long, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, float, 3 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, double, 3 );
> >>
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned char, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed char, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned short, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed short, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, unsigned long, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, signed long, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, float, 4 );
> >> FIXEDARRAYSTATICTRAITSMACRO( Vector, double, 4 );
> >>
> >> /** Define a macro to be used for all (variable) array types. */
> >> #define VARIABLEARRAYSTATICTRAITSMACRO( T, E ) \
> >> template<> \
> >> class VectorPixelTraits< T<E> > { \
> >> public: \
> >>  static unsigned int GetNumberOfComponents(T<E> input) { return
> >> input.Size(); } \
> >>  static E *GetElement( unsigned int i, T<E> *pixel) { return
> >> &((*pixel)[i]); } \
> >>  static void SetElement( unsigned int i, T<E> &left, T<E> right) {
> >> left[i] = right[i]; } \
> >>  static T<E> ZeroValue( T<E> input ) { return
> >> NumericTraits<T<E>>::Zero(input); } \
> >>  static T<E> Convert( double input ) { T<E> value; /* NOT IMPLEMENTED
> >> */ return value; } \
> >> }; \
> >>
> >> VARIABLEARRAYSTATICTRAITSMACRO( VariableLengthVector, unsigned char );
> >> VARIABLEARRAYSTATICTRAITSMACRO( VariableLengthVector, signed char );
> >> VARIABLEARRAYSTATICTRAITSMACRO( VariableLengthVector, unsigned short );
> >> VARIABLEARRAYSTATICTRAITSMACRO( VariableLengthVector, signed short );
> >> VARIABLEARRAYSTATICTRAITSMACRO( VariableLengthVector, unsigned long );
> >> VARIABLEARRAYSTATICTRAITSMACRO( VariableLengthVector, signed long );
> >> VARIABLEARRAYSTATICTRAITSMACRO( VariableLengthVector, float );
> >> VARIABLEARRAYSTATICTRAITSMACRO( VariableLengthVector, double );
> >>
> >> } // end namespace itk
> >>
> >> #endif
> >>
> >>
> >> On 28 December 2010 09:52, Ali Habib <ali.mahmoud.habib at gmail.com>
> wrote:
> >> > Dear All,
> >> > I need the pixel data as unsigned char* , I created my pipeline but I
> >> > stuck
> >> > on how to get the buffer data , also I need to know does the
> pixel_value
> >> > will show me if the input is scaler or not
> >> > the code I use is :
> >> > typedef signed short InputPixelType;
> >> > const unsigned int   InputDimension = 2;
> >> > typedef itk::Image< InputPixelType, InputDimension > InputImageType;
> >> > typedef itk::ImageFileReader< InputImageType > ReaderType;
> >> > typedef InputImageType::SizeType         SizeType;
> >> > ReaderType::Pointer reader = ReaderType::New();
> >> > reader->SetFileName( "4.dcm" );
> >> > typedef itk::GDCMImageIO           ImageIOType;
> >> > ImageIOType::Pointer gdcmImageIO = ImageIOType::New();
> >> > reader->SetImageIO( gdcmImageIO );
> >> > try
> >> >     {
> >> > reader->Update();
> >> >     }
> >> > catch (itk::ExceptionObject & e)
> >> >     {
> >> > std::cerr << "exception in file reader " << std::endl;
> >> > std::cerr << e << std::endl;
> >> > //          return EXIT_FAILURE;
> >> >     }
> >> > InputImageType::Pointer image_1 = reader->GetOutput() ;
> >> > // the image parameters
> >> > unsigned long lwidth =
> image_1->GetLargestPossibleRegion().GetSize()[0]
> >> > ;
> >> > unsigned long lheight =
> image_1->GetLargestPossibleRegion().GetSize()[1]
> >> > ;
> >> > InputImageType::IndexType index;
> >> > index[0]=1;
> >> > index[1]=1;
> >> > signed short pixel_value;
> >> > pixel_value= image_1->GetPixel( index );
> >
> >
>
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