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

    Click :ref:`here <sphx_glr_download_advanced_image_processing_auto_examples_plot_GMM.py>` to download the full example code
.. rst-class:: sphx-glr-example-title

.. _sphx_glr_advanced_image_processing_auto_examples_plot_GMM.py:


Segmentation with Gaussian mixture models
=========================================

This example performs a Gaussian mixture model analysis of the image
histogram to find the right thresholds for separating foreground from
background.





.. image:: /advanced/image_processing/auto_examples/images/sphx_glr_plot_GMM_001.png
    :class: sphx-glr-single-img





.. code-block:: python


    import numpy as np
    from scipy import ndimage
    import matplotlib.pyplot as plt
    from sklearn.mixture import GaussianMixture

    np.random.seed(1)
    n = 10
    l = 256
    im = np.zeros((l, l))
    points = l*np.random.random((2, n**2))
    im[(points[0]).astype(np.int), (points[1]).astype(np.int)] = 1
    im = ndimage.gaussian_filter(im, sigma=l/(4.*n))

    mask = (im > im.mean()).astype(np.float)


    img = mask + 0.3*np.random.randn(*mask.shape)

    hist, bin_edges = np.histogram(img, bins=60)
    bin_centers = 0.5*(bin_edges[:-1] + bin_edges[1:])

    classif = GaussianMixture(n_components=2)
    classif.fit(img.reshape((img.size, 1)))

    threshold = np.mean(classif.means_)
    binary_img = img > threshold


    plt.figure(figsize=(11,4))

    plt.subplot(131)
    plt.imshow(img)
    plt.axis('off')
    plt.subplot(132)
    plt.plot(bin_centers, hist, lw=2)
    plt.axvline(0.5, color='r', ls='--', lw=2)
    plt.text(0.57, 0.8, 'histogram', fontsize=20, transform = plt.gca().transAxes)
    plt.yticks([])
    plt.subplot(133)
    plt.imshow(binary_img, cmap=plt.cm.gray, interpolation='nearest')
    plt.axis('off')

    plt.subplots_adjust(wspace=0.02, hspace=0.3, top=1, bottom=0.1, left=0, right=1)
    plt.show()

**Total running time of the script:** ( 0 minutes  0.248 seconds)


.. _sphx_glr_download_advanced_image_processing_auto_examples_plot_GMM.py:


.. only :: html

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



  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_