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.. _sphx_glr_auto_examples_plot_OTDA_color_images.py:


========================================================
OT for domain adaptation with image color adaptation [6]
========================================================

[6] Ferradans, S., Papadakis, N., Peyre, G., & Aujol, J. F. (2014). Regularized discrete optimal transport. SIAM Journal on Imaging Sciences, 7(3), 1853-1882.




.. rst-class:: sphx-glr-horizontal


    *

      .. image:: /auto_examples/images/sphx_glr_plot_OTDA_color_images_001.png
            :scale: 47

    *

      .. image:: /auto_examples/images/sphx_glr_plot_OTDA_color_images_002.png
            :scale: 47





.. code-block:: python


    import numpy as np
    import scipy.ndimage as spi
    import matplotlib.pylab as pl
    import ot


    #%% Loading images

    I1=spi.imread('../data/ocean_day.jpg').astype(np.float64)/256
    I2=spi.imread('../data/ocean_sunset.jpg').astype(np.float64)/256

    #%% Plot images

    pl.figure(1)

    pl.subplot(1,2,1)
    pl.imshow(I1)
    pl.title('Image 1')

    pl.subplot(1,2,2)
    pl.imshow(I2)
    pl.title('Image 2')

    pl.show()

    #%% Image conversion and dataset generation

    def im2mat(I):
        """Converts and image to matrix (one pixel per line)"""
        return I.reshape((I.shape[0]*I.shape[1],I.shape[2]))

    def mat2im(X,shape):
        """Converts back a matrix to an image"""
        return X.reshape(shape)

    X1=im2mat(I1)
    X2=im2mat(I2)

    # training samples
    nb=1000
    idx1=np.random.randint(X1.shape[0],size=(nb,))
    idx2=np.random.randint(X2.shape[0],size=(nb,))

    xs=X1[idx1,:]
    xt=X2[idx2,:]

    #%% Plot image distributions


    pl.figure(2,(10,5))

    pl.subplot(1,2,1)
    pl.scatter(xs[:,0],xs[:,2],c=xs)
    pl.axis([0,1,0,1])
    pl.xlabel('Red')
    pl.ylabel('Blue')
    pl.title('Image 1')

    pl.subplot(1,2,2)
    #pl.imshow(I2)
    pl.scatter(xt[:,0],xt[:,2],c=xt)
    pl.axis([0,1,0,1])
    pl.xlabel('Red')
    pl.ylabel('Blue')
    pl.title('Image 2')

    pl.show()



    #%% domain adaptation between images

    # LP problem
    da_emd=ot.da.OTDA()     # init class
    da_emd.fit(xs,xt)       # fit distributions


    # sinkhorn regularization
    lambd=1e-1
    da_entrop=ot.da.OTDA_sinkhorn()
    da_entrop.fit(xs,xt,reg=lambd)



    #%% prediction between images (using out of sample prediction as in [6])

    X1t=da_emd.predict(X1)
    X2t=da_emd.predict(X2,-1)


    X1te=da_entrop.predict(X1)
    X2te=da_entrop.predict(X2,-1)


    def minmax(I):
        return np.minimum(np.maximum(I,0),1)

    I1t=minmax(mat2im(X1t,I1.shape))
    I2t=minmax(mat2im(X2t,I2.shape))

    I1te=minmax(mat2im(X1te,I1.shape))
    I2te=minmax(mat2im(X2te,I2.shape))

    #%% plot all images

    pl.figure(2,(10,8))

    pl.subplot(2,3,1)

    pl.imshow(I1)
    pl.title('Image 1')

    pl.subplot(2,3,2)
    pl.imshow(I1t)
    pl.title('Image 1 Adapt')


    pl.subplot(2,3,3)
    pl.imshow(I1te)
    pl.title('Image 1 Adapt (reg)')

    pl.subplot(2,3,4)

    pl.imshow(I2)
    pl.title('Image 2')

    pl.subplot(2,3,5)
    pl.imshow(I2t)
    pl.title('Image 2 Adapt')


    pl.subplot(2,3,6)
    pl.imshow(I2te)
    pl.title('Image 2 Adapt (reg)')

    pl.show()

**Total running time of the script:** ( 0 minutes  24.815 seconds)



.. container:: sphx-glr-footer


  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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

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

    `Generated by Sphinx-Gallery <http://sphinx-gallery.readthedocs.io>`_