.. _viewing_images:

==============
Viewing Images
==============

.. rubric:: How to use other packages with pydicom to view DICOM images

Introduction
============

pydicom is mainly concerned with getting at the DICOM data elements in files, 
but it is often desirable to view pixel data as an image. 
There are several options:

  * Use any of the many `DICOM viewer 
    <http://www.dclunie.com/medical-image-faq/html/part8.html#DICOMFileConvertorsAndViewers>`_
    programs available
  * use pydicom with `matplotlib <http://matplotlib.sourceforge.net/>`_
  * use pydicom with Tkinter (comes standard with python)
  * use pydicom with the `Python Imaging Library (PIL) 
    <http://www.pythonware.com/products/pil/>`_
  * use pydicom with `wxPython <http://www.wxpython.org/>`_

Using pydicom with matplotlib
=============================

matplotlib is available at http://matplotlib.sourceforge.net/. It 
can take 2-d image information from ``Dataset.pixel_array`` and display it. 
Here is an example::

    >>> import dicom
    >>> import pylab
    >>> ds=dicom.read_file("CT_small.dcm")
    >>> pylab.imshow(ds.pixel_array, cmap=pylab.cm.bone)
    <matplotlib.image.AxesImage object at 0x0162A530>
    >>> pylab.show()
    >>>

Thanks to Roy Keyes for pointing out how to do this.


Using pydicom with Tkinter
==========================

The program `pydicom_Tkinter.py 
<http://code.google.com/p/pydicom/source/browse/source/dicom/contrib/pydicom_Tkinter.py>`_
in the ``contrib`` folder demonstrates how to show an image using the 
Tkinter graphics system, which comes standard with most python installs.
It creates a Tkinter PhotoImage in a Label widget or a user-supplied widget.


Using pydicom with Python Imaging Library (PIL)
===============================================

The module `pydicom_PIL.py 
<http://code.google.com/p/pydicom/source/browse/source/dicom/contrib/pydicom_PIL.py>`_
in the ``contrib`` folder
uses PIL's ``Image.show()`` method after creating an Image instance
from the pixel data and some basic information about it (bit depth, LUTs, etc)


Using pydicom with wxPython
===========================

The module `imViewer-Simple.py 
<http://code.google.com/p/pydicom/source/browse/source/dicom/contrib/imViewer_Simple.py>`_
in the ``contrib`` folder uses wxPython (also PIL, but it notes that it 
may not be strictly necessary) to display an image from a pydicom dataset.