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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: VectorImage.cxx
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.
=========================================================================*/
#if defined(_MSC_VER)
#pragma warning ( disable : 4786 )
#endif
// Software Guide : BeginLatex
//
// Many image processing tasks require images of non-scalar pixel type. A
// typical example is an image of vectors. This is the image type required to
// represent the gradient of a scalar image. The following code illustrates
// how to instantiate and use an image whose pixels are of vector type.
//
// For convenience we use the \doxygen{Vector} class to define the pixel
// type. The Vector class is intended to represent a geometrical vector in
// space. It is not intended to be used as an array container like the
// \href{http://www.sgi.com/tech/stl/Vector.html}{\code{std::vector}} in
// \href{http://www.sgi.com/tech/stl/}{STL}. If you are interested in
// containers, the \doxygen{VectorContainer} class may provide the
// functionality you want.
//
// \index{itk::Vector}
// \index{itk::Vector!header}
//
//
// The first step is to include the header file of the Vector class.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkVector.h"
// Software Guide : EndCodeSnippet
#include "itkImage.h"
int main(int, char *[])
{
// Software Guide : BeginLatex
//
// The Vector class is templated over the type used to represent
// the coordinate in space and over the dimension of the space. In this example,
// we want the vector dimension to match the image dimension, but this is by
// no means a requirement. We could have defined a four-dimensional image
// with three-dimensional vectors as pixels.
//
// \index{itk::Vector!Instantiation}
// \index{itk::Vector!itk::Image}
// \index{itk::Image!Vector pixel}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
typedef itk::Vector< float, 3 > PixelType;
typedef itk::Image< PixelType, 3 > ImageType;
// Software Guide : EndCodeSnippet
// Then the image object can be created
ImageType::Pointer image = ImageType::New();
// The image region should be initialized
ImageType::IndexType start;
ImageType::SizeType size;
size[0] = 200; // size along X
size[1] = 200; // size along Y
size[2] = 200; // size along Z
start[0] = 0; // first index on X
start[1] = 0; // first index on Y
start[2] = 0; // first index on Z
ImageType::RegionType region;
region.SetSize( size );
region.SetIndex( start );
// Pixel data is allocated
image->SetRegions( region );
image->Allocate();
// The image buffer is initialized to a particular value
ImageType::PixelType initialValue;
// A vector can initialize all its components to the
// same value by using the Fill() method.
initialValue.Fill( 0.0 );
// Now the image buffer can be initialized with this
// vector value.
image->FillBuffer( initialValue );
ImageType::IndexType pixelIndex;
pixelIndex[0] = 27; // x position
pixelIndex[1] = 29; // y position
pixelIndex[2] = 37; // z position
// Software Guide : BeginLatex
//
// The Vector class inherits the operator \code{[]} from the
// \doxygen{FixedArray} class. This makes it possible to access the
// Vector's components using index notation.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
ImageType::PixelType pixelValue;
pixelValue[0] = 1.345; // x component
pixelValue[1] = 6.841; // y component
pixelValue[2] = 3.295; // x component
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We can now store this vector in one of the image pixels by defining an
// index and invoking the \code{SetPixel()} method.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
image->SetPixel( pixelIndex, pixelValue );
// Software Guide : EndCodeSnippet
// The GetPixel method can also be used to read Vectors
// pixels from the image
ImageType::PixelType value = image->GetPixel( pixelIndex );
// Lets repeat that both \code{SetPixel()} and \code{GetPixel()} are
// inefficient and should only be used for debugging purposes or for
// implementing interactions with a graphical user interface such as
// querying pixel value by clicking with the mouse.
return 0;
}
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