.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "11_demos\python_packages\scipy\demo_Scipy.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        Click :ref:`here <sphx_glr_download_11_demos_python_packages_scipy_demo_Scipy.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_11_demos_python_packages_scipy_demo_Scipy.py:

Scipy
=======

Opens the ascent image from ``scipy.misc`` and shifts the image.
Finally, the shift offsets are determined using cross-correlation.

.. GENERATED FROM PYTHON SOURCE LINES 7-13

.. code-block:: default

    import scipy.misc
    import numpy
    from numpy.fft import fft2
    from numpy.fft import fftshift
    import pylab








.. GENERATED FROM PYTHON SOURCE LINES 15-16

Get the ascent image and calculate an offset shift.

.. GENERATED FROM PYTHON SOURCE LINES 16-40

.. code-block:: default

    ascent = scipy.misc.ascent()
    print("The ascent-image has a size of", ascent.shape)
    print("The maximum value of this image is ", ascent.max())
    print("Its data type is ", ascent.dtype)

    F = fft2(ascent)
    F2 = fftshift(F)

    pylab.figure()
    pylab.gray()
    pylab.subplot(221)
    pylab.imshow(ascent)
    pylab.title("ascent (Original)")

    pylab.subplot(222)
    img = pylab.imshow(numpy.real(F))
    img.set_clim(0, 100)
    pylab.title("ascent (FFT)")

    pylab.subplot(223)
    img = pylab.imshow(numpy.real(F2))
    img.set_clim(0, 100)
    pylab.title("ascent (FFT), fftshift")




.. image-sg:: /11_demos/python_packages/scipy/images/sphx_glr_demo_Scipy_001.png
   :alt: ascent (Original), ascent (FFT), ascent (FFT), fftshift
   :srcset: /11_demos/python_packages/scipy/images/sphx_glr_demo_Scipy_001.png
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    The ascent-image has a size of (512, 512)
    The maximum value of this image is  255
    Its data type is  int32

    Text(0.5, 1.0, 'ascent (FFT), fftshift')



.. GENERATED FROM PYTHON SOURCE LINES 41-42

Calculate the cross-correlation. 

.. GENERATED FROM PYTHON SOURCE LINES 42-84

.. code-block:: default

    pylab.figure()
    pylab.subplot(231)
    pylab.imshow(ascent)

    ascent_roll = numpy.roll(ascent, 50, 1)
    ascent_roll = numpy.roll(ascent_roll, -150, 0)

    pylab.subplot(232)
    pylab.imshow(ascent_roll)

    F = fftshift(fft2(ascent))
    F2 = fftshift(fft2(ascent_roll))

    F3 = numpy.multiply(F, F2.conj())

    F4 = fftshift(numpy.fft.ifft2(F3))

    pylab.subplot(233)
    img = pylab.imshow(numpy.real(F))
    img.set_clim(0, 100)

    pylab.subplot(234)
    img = pylab.imshow(numpy.real(F2))
    img.set_clim(0, 100)

    pylab.subplot(235)
    img = pylab.imshow(numpy.real(F3))
    img.set_clim(0, 100)

    pylab.subplot(236)
    F5 = numpy.real(F4)
    img = pylab.imshow(F5, vmin=0, vmax=0.001)

    max_pos = numpy.argmax(F5)

    offset_x = max_pos % 512
    offset_y = (max_pos - offset_x) / 512

    print("offset_x: ", offset_x - 256)
    print("offset_y: ", offset_y - 256)

    pylab.show()



.. image-sg:: /11_demos/python_packages/scipy/images/sphx_glr_demo_Scipy_002.png
   :alt: demo Scipy
   :srcset: /11_demos/python_packages/scipy/images/sphx_glr_demo_Scipy_002.png
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    offset_x:  -50
    offset_y:  150.0





.. rst-class:: sphx-glr-timing

   **Total running time of the script:** ( 0 minutes  0.693 seconds)


.. _sphx_glr_download_11_demos_python_packages_scipy_demo_Scipy.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example


    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: demo_Scipy.py <demo_Scipy.py>`

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: demo_Scipy.ipynb <demo_Scipy.ipynb>`