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/home/glehmann/rpm/BUILD/InsightToolkit-2.8.1/Code/Common/itkImageRegionConstIterator.h Class Reference
[Image Iterators]

#include <itkImageRegionConstIterator.h>


Detailed Description

A multi-dimensional iterator templated over image type that walks a region of pixels.

The itk::ImageRegionConstIterator is optimized for iteration speed and is the first choice for iterative, pixel-wise operations on an image. ImageRegionIterator is the least specialized of the ITK image iterator classes. ImageRegionConstIterator is templated over the image type, and is constrained to walk only within the specified region and along a line parallel to one of the coordinate axes, "wrapping" to the next line as it reaches the boundary of the image. To walk the entire image, specify the region to be image->GetRequestedRegion().

ImageRegionConstIterator provides read-only access to image data. It is the base class for the read/write access ImageRegionIterator.

ImageRegionConstIterator is a multi-dimensional iterator, requiring more information be specified before the iterator can be used than conventional iterators. Whereas the std::vector::iterator from the STL only needs to be passed a pointer to establish the iterator, the multi-dimensional image iterator needs a pointer, the size of the buffer, the size of the region, the start index of the buffer, and the start index of the region. To gain access to this information, ImageRegionConstIterator holds a reference to the image over which it is traversing.

ImageRegionConstIterator assumes a particular layout of the image data. The is arranged in a 1D array as if it were [][][][slice][row][col] with Index[0] = col, Index[1] = row, Index[2] = slice, etc.

operator++ provides a simple syntax for walking around a region of a multidimensional image. operator++ iterates across a row, constraining the movement to within a region of image. When the iterator reaches the boundary of the region along a row, the iterator automatically wraps to the next row, starting at the first pixel in the row that is part of the region. This allows for simple processing loops of the form:

      it = it.Begin();
      for (; !it.IsAtEnd(); ++it)
         {
         *it += 100.0;
         }

MORE INFORMATION
For a complete description of the ITK Image Iterators and their API, please see the Iterators chapter in the ITK Software Guide. The ITK Software Guide is available in print and as a free .pdf download from http://www.itk.org.


The documentation for this class was generated from the following file:
Generated at Sat Sep 2 21:22:49 2006 for ITK by doxygen 1.4.7 written by Dimitri van Heesch, © 1997-2000