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+
+
+.. _sphx_glr_auto_examples_plot_convolutional_barycenter.py:
+
+
+============================================
+Convolutional Wasserstein Barycenter example
+============================================
+
+This example is designed to illustrate how the Convolutional Wasserstein Barycenter
+function of POT works.
+
+
+
+.. code-block:: python
+
+
+ # Author: Nicolas Courty <ncourty@irisa.fr>
+ #
+ # License: MIT License
+
+
+ import numpy as np
+ import pylab as pl
+ import ot
+
+
+
+
+
+
+
+Data preparation
+----------------
+
+The four distributions are constructed from 4 simple images
+
+
+
+.. code-block:: python
+
+
+
+ f1 = 1 - pl.imread('../data/redcross.png')[:, :, 2]
+ f2 = 1 - pl.imread('../data/duck.png')[:, :, 2]
+ f3 = 1 - pl.imread('../data/heart.png')[:, :, 2]
+ f4 = 1 - pl.imread('../data/tooth.png')[:, :, 2]
+
+ A = []
+ f1 = f1 / np.sum(f1)
+ f2 = f2 / np.sum(f2)
+ f3 = f3 / np.sum(f3)
+ f4 = f4 / np.sum(f4)
+ A.append(f1)
+ A.append(f2)
+ A.append(f3)
+ A.append(f4)
+ A = np.array(A)
+
+ nb_images = 5
+
+ # those are the four corners coordinates that will be interpolated by bilinear
+ # interpolation
+ v1 = np.array((1, 0, 0, 0))
+ v2 = np.array((0, 1, 0, 0))
+ v3 = np.array((0, 0, 1, 0))
+ v4 = np.array((0, 0, 0, 1))
+
+
+
+
+
+
+
+
+Barycenter computation and visualization
+----------------------------------------
+
+
+
+
+.. code-block:: python
+
+
+ pl.figure(figsize=(10, 10))
+ pl.title('Convolutional Wasserstein Barycenters in POT')
+ cm = 'Blues'
+ # regularization parameter
+ reg = 0.004
+ for i in range(nb_images):
+ for j in range(nb_images):
+ pl.subplot(nb_images, nb_images, i * nb_images + j + 1)
+ tx = float(i) / (nb_images - 1)
+ ty = float(j) / (nb_images - 1)
+
+ # weights are constructed by bilinear interpolation
+ tmp1 = (1 - tx) * v1 + tx * v2
+ tmp2 = (1 - tx) * v3 + tx * v4
+ weights = (1 - ty) * tmp1 + ty * tmp2
+
+ if i == 0 and j == 0:
+ pl.imshow(f1, cmap=cm)
+ pl.axis('off')
+ elif i == 0 and j == (nb_images - 1):
+ pl.imshow(f3, cmap=cm)
+ pl.axis('off')
+ elif i == (nb_images - 1) and j == 0:
+ pl.imshow(f2, cmap=cm)
+ pl.axis('off')
+ elif i == (nb_images - 1) and j == (nb_images - 1):
+ pl.imshow(f4, cmap=cm)
+ pl.axis('off')
+ else:
+ # call to barycenter computation
+ pl.imshow(ot.bregman.convolutional_barycenter2d(A, reg, weights), cmap=cm)
+ pl.axis('off')
+ pl.show()
+
+
+
+.. image:: /auto_examples/images/sphx_glr_plot_convolutional_barycenter_001.png
+ :align: center
+
+
+
+
+**Total running time of the script:** ( 1 minutes 11.608 seconds)
+
+
+
+.. only :: html
+
+ .. container:: sphx-glr-footer
+
+
+ .. container:: sphx-glr-download
+
+ :download:`Download Python source code: plot_convolutional_barycenter.py <plot_convolutional_barycenter.py>`
+
+
+
+ .. container:: sphx-glr-download
+
+ :download:`Download Jupyter notebook: plot_convolutional_barycenter.ipynb <plot_convolutional_barycenter.ipynb>`
+
+
+.. only:: html
+
+ .. rst-class:: sphx-glr-signature
+
+ `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_