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DataRepresentation/Image/VectorImage.cxx

00001 /*=========================================================================
00002 
00003   Program:   Insight Segmentation & Registration Toolkit
00004   Module:    $RCSfile: VectorImage.cxx,v $
00005   Language:  C++
00006   Date:      $Date: 2005-02-08 03:51:53 $
00007   Version:   $Revision: 1.12 $
00008 
00009   Copyright (c) Insight Software Consortium. All rights reserved.
00010   See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
00011 
00012      This software is distributed WITHOUT ANY WARRANTY; without even 
00013      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
00014      PURPOSE.  See the above copyright notices for more information.
00015 
00016 =========================================================================*/
00017 #if defined(_MSC_VER)
00018 #pragma warning ( disable : 4786 )
00019 #endif
00020 
00021 // Software Guide : BeginLatex
00022 //
00023 // Many image processing tasks require images of non-scalar pixel type. A
00024 // typical example is an image of vectors. This is the image type required to
00025 // represent the gradient of a scalar image. The following code illustrates
00026 // how to instantiate and use an image whose pixels are of vector type.
00027 //
00028 // For convenience we use the \doxygen{Vector} class to define the pixel
00029 // type.  The Vector class is intended to represent a geometrical vector in
00030 // space. It is not intended to be used as an array container like the
00031 // \href{http://www.sgi.com/tech/stl/Vector.html}{\code{std::vector}} in
00032 // \href{http://www.sgi.com/tech/stl/}{STL}.  If you are interested in
00033 // containers, the \doxygen{VectorContainer} class may provide the
00034 // functionality you want.
00035 //
00036 // \index{itk::Vector}
00037 // \index{itk::Vector!header}
00038 //
00039 //
00040 // The first step is to include the header file of the Vector class.
00041 //
00042 // Software Guide : EndLatex 
00043 
00044 // Software Guide : BeginCodeSnippet
00045 #include "itkVector.h"
00046 // Software Guide : EndCodeSnippet
00047 
00048 
00049 #include "itkImage.h"
00050 
00051 int main(int, char *[])
00052 {
00053   // Software Guide : BeginLatex
00054   // 
00055   // The Vector class is templated over the type used to represent
00056   // the coordinate in space and over the dimension of the space.  In this example,
00057   // we want the vector dimension to match the image dimension, but this is by
00058   // no means a requirement. We could have defined a four-dimensional image
00059   // with three-dimensional vectors as pixels.
00060   //
00061   // \index{itk::Vector!Instantiation}
00062   // \index{itk::Vector!itk::Image}
00063   // \index{itk::Image!Vector pixel}
00064   //
00065   // Software Guide : EndLatex 
00066 
00067   // Software Guide : BeginCodeSnippet
00068   typedef itk::Vector< float, 3 >       PixelType;
00069   typedef itk::Image< PixelType, 3 >    ImageType;
00070   // Software Guide : EndCodeSnippet
00071 
00072   // Then the image object can be created
00073   ImageType::Pointer image = ImageType::New();
00074 
00075   // The image region should be initialized
00076   ImageType::IndexType start;
00077   ImageType::SizeType  size;
00078 
00079   size[0]  = 200;  // size along X
00080   size[1]  = 200;  // size along Y
00081   size[2]  = 200;  // size along Z
00082 
00083   start[0] =   0;  // first index on X
00084   start[1] =   0;  // first index on Y
00085   start[2] =   0;  // first index on Z
00086 
00087   ImageType::RegionType region;
00088   region.SetSize( size );
00089   region.SetIndex( start );
00090   
00091   // Pixel data is allocated
00092   image->SetRegions( region );
00093   image->Allocate();
00094 
00095   // The image buffer is initialized to a particular value
00096   ImageType::PixelType  initialValue;
00097 
00098   // A vector can initialize all its components to the
00099   // same value by using the Fill() method.
00100   initialValue.Fill( 0.0 );
00101 
00102   // Now the image buffer can be initialized with this
00103   // vector value.
00104   image->FillBuffer( initialValue );
00105 
00106   ImageType::IndexType pixelIndex;
00107  
00108   pixelIndex[0] = 27;   // x position
00109   pixelIndex[1] = 29;   // y position
00110   pixelIndex[2] = 37;   // z position
00111 
00112 
00113   // Software Guide : BeginLatex
00114   //
00115   // The Vector class inherits the operator \code{[]} from the
00116   // \doxygen{FixedArray} class. This makes it possible to access the
00117   // Vector's components using index notation.
00118   //
00119   // Software Guide : EndLatex 
00120 
00121   // Software Guide : BeginCodeSnippet
00122   ImageType::PixelType   pixelValue;
00123 
00124   pixelValue[0] =  1.345;   // x component
00125   pixelValue[1] =  6.841;   // y component
00126   pixelValue[2] =  3.295;   // x component
00127   // Software Guide : EndCodeSnippet
00128 
00129 
00130   // Software Guide : BeginLatex
00131   //
00132   // We can now store this vector in one of the image pixels by defining an
00133   // index and invoking the \code{SetPixel()} method.
00134   //
00135   // Software Guide : EndLatex 
00136 
00137   // Software Guide : BeginCodeSnippet
00138   image->SetPixel(   pixelIndex,   pixelValue  );
00139   // Software Guide : EndCodeSnippet
00140 
00141 
00142   // The GetPixel method can also be used to read Vectors 
00143   // pixels from the image
00144   ImageType::PixelType value = image->GetPixel( pixelIndex );
00145 
00146 
00147   // Lets repeat that both \code{SetPixel()} and \code{GetPixel()} are
00148   // inefficient and should only be used for debugging purposes or for
00149   // implementing interactions with a graphical user interface such as
00150   // querying pixel value by clicking with the mouse.
00151 
00152   return 0;
00153 }
00154 

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