Create an Image#

Synopsis#

This example illustrates how to manually construct Image.

This example illustrates how to manually construct an itk::Image class. The following is the minimal code needed to instantiate, declare and create the Image class.

Results#

Image (0x1eb5f10)
  RTTI typeinfo:   itk::Image<unsigned char, 3u>
  Reference Count: 1
  Modified Time: 4
  Debug: Off
  Object Name:
  Observers:
    none
  Source: (none)
  Source output name: (none)
  Release Data: Off
  Data Released: False
  Global Release Data: Off
  PipelineMTime: 0
  UpdateMTime: 0
  RealTimeStamp: 0 seconds
  LargestPossibleRegion:
    Dimension: 3
    Index: [0, 0, 0]
    Size: [200, 200, 200]
  BufferedRegion:
    Dimension: 3
    Index: [0, 0, 0]
    Size: [200, 200, 200]
  RequestedRegion:
    Dimension: 3
    Index: [0, 0, 0]
    Size: [200, 200, 200]
  Spacing: [1, 1, 1]
  Origin: [0, 0, 0]
  Direction:
1 0 0
0 1 0
0 0 1

  IndexToPointMatrix:
1 0 0
0 1 0
0 0 1

  PointToIndexMatrix:
1 0 0
0 1 0
0 0 1

  Inverse Direction:
1 0 0
0 1 0
0 0 1

  PixelContainer:
    ImportImageContainer (0x1a678a0)
      RTTI typeinfo:   itk::ImportImageContainer<unsigned long, unsigned char>
      Reference Count: 1
      Modified Time: 5
      Debug: Off
      Object Name:
      Observers:
        none
      Pointer: 0x7facf287d010
      Container manages memory: true
      Size: 8000000
      Capacity: 8000000

Code#

Python#

#!/usr/bin/env python

import itk

Dimension = 3
PixelType = itk.ctype("unsigned char")
ImageType = itk.Image[PixelType, Dimension]

image = ImageType.New()

start = itk.Index[Dimension]()
start[0] = 0  # first index on X
start[1] = 0  # first index on Y
start[2] = 0  # first index on Z

size = itk.Size[Dimension]()
size[0] = 200  # size along X
size[1] = 200  # size along Y
size[2] = 200  # size along Z

region = itk.ImageRegion[Dimension]()
region.SetSize(size)
region.SetIndex(start)

image.SetRegions(region)
image.Allocate()

print(image)

C++#

#include "itkImage.h"

int
main()
{
  using ImageType = itk::Image<unsigned char, 3>;
  auto image = ImageType::New();

  ImageType::IndexType start;
  start[0] = 0; // first index on X
  start[1] = 0; // first index on Y
  start[2] = 0; // first index on Z

  ImageType::SizeType size;
  size[0] = 200; // size along X
  size[1] = 200; // size along Y
  size[2] = 200; // size along Z

  ImageType::RegionType region;
  region.SetSize(size);
  region.SetIndex(start);

  image->SetRegions(region);
  image->Allocate();

  std::cout << image << std::endl;

  return EXIT_SUCCESS;
}

Classes demonstrated#

template<typename TPixel, unsigned int VImageDimension = 2> class Image : public itk::ImageBase<VImageDimension>

Templated n-dimensional image class.

Images are templated over a pixel type (modeling the dependent variables), and a dimension (number of independent variables). The container for the pixel data is the ImportImageContainer.

Within the pixel container, images are modelled as arrays, defined by a start index and a size.

The superclass of Image, ImageBase, defines the geometry of the image in terms of where the image sits in physical space, how the image is oriented in physical space, the size of a pixel, and the extent of the image itself. ImageBase provides the methods to convert between the index and physical space coordinate frames.

Pixels can be accessed directly using the SetPixel() and GetPixel() methods or can be accessed via iterators that define the region of the image they traverse.

The pixel type may be one of the native types; a Insight-defined class type such as Vector; or a user-defined type. Note that depending on the type of pixel that you use, the process objects (i.e., those filters processing data objects) may not operate on the image and/or pixel type. This becomes apparent at compile-time because operator overloading (for the pixel type) is not supported.

The data in an image is arranged in a 1D array as [][][][slice][row][col] with the column index varying most rapidly. The Index type reverses the order so that with Index[0] = col, Index[1] = row, Index[2] = slice, …

See

ImageBase

See

ImageContainerInterface

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