Finishing Up Persons Using Machine Learning

This example shows the use of various machine learning algorithms to complete images. The goal is to predict the lower half of the face, given its upper half.

The first column of images shows real faces. The following columns illustrate how trees (extremely randomized trees), the k-nearest neighbor method (k nearest neighbors / K-nn), linear regression (linear regression) and RidgeCV (ridge regression complete) complete the bottom half of these individuals.

#   import numpy as np import matplotlib.pyplot as plt from sklearn.datasets import fetch_olivetti_faces from sklearn.utils.validation import check_random_state from sklearn.ensemble import ExtraTreesRegressor from sklearn.neighbors import KNeighborsRegressor from sklearn.linear_model import LinearRegression from sklearn.linear_model import RidgeCV #    data = fetch_olivetti_faces() targets = data.target data = data.images.reshape((len(data.images), -1)) train = data[targets < 30] test = data[targets >= 30] # Test on independent people #     n_faces = 5 rng = check_random_state(4) face_ids = rng.randint(test.shape[0], size=(n_faces, )) test = test[face_ids, :] n_pixels = data.shape[1] #    X_train = train[:, :(n_pixels + 1) // 2] #    y_train = train[:, n_pixels // 2:] X_test = test[:, :(n_pixels + 1) // 2] y_test = test[:, n_pixels // 2:] #   ESTIMATORS = { "Extra trees": ExtraTreesRegressor(n_estimators=10, max_features=32, random_state=0), "K-nn": KNeighborsRegressor(), "Linear regression": LinearRegression(), "Ridge": RidgeCV(), } y_test_predict = dict() for name, estimator in ESTIMATORS.items(): estimator.fit(X_train, y_train) y_test_predict[name] = estimator.predict(X_test) #  image_shape = (64, 64) n_cols = 1 + len(ESTIMATORS) plt.figure(figsize=(2. * n_cols, 2.26 * n_faces)) plt.suptitle("       ", size=16) for i in range(n_faces): true_face = np.hstack((X_test[i], y_test[i])) if i: sub = plt.subplot(n_faces, n_cols, i * n_cols + 1) else: sub = plt.subplot(n_faces, n_cols, i * n_cols + 1, title="true faces") sub.axis("off") sub.imshow(true_face.reshape(image_shape), cmap=plt.cm.gray, interpolation="nearest") for j, est in enumerate(sorted(ESTIMATORS)): completed_face = np.hstack((X_test[i], y_test_predict[est][i])) if i: sub = plt.subplot(n_faces, n_cols, i * n_cols + 2 + j) else: sub = plt.subplot(n_faces, n_cols, i * n_cols + 2 + j, title=est) sub.axis("off") sub.imshow(completed_face.reshape(image_shape), cmap=plt.cm.gray, interpolation="nearest") plt.show()