def create_class_visualization(target_y, model, **kwargs):
"""
Perform optimization over the image to generate class visualizations.
Inputs:
- target_y: Integer in the range [0, 100) giving the target class
- model: A PretrainedCNN that will be used for generation
Keyword arguments:
- learning_rate: Floating point number giving the learning rate
- blur_every: An integer; how often to blur the image as a regularizer
- l2_reg: Floating point number giving L2 regularization strength on the image;
this is lambda in the equation above.
- max_jitter: How much random jitter to add to the image as regularization
- num_iterations: How many iterations to run for
- show_every: How often to show the image
"""
learning_rate = kwargs.pop('learning_rate', 10000)
blur_every = kwargs.pop('blur_every', 1)
l2_reg = kwargs.pop('l2_reg', 1e-6)
max_jitter = kwargs.pop('max_jitter', 4)
num_iterations = kwargs.pop('num_iterations', 100)
show_every = kwargs.pop('show_every', 25)
X = np.random.randn(1, 3, 64, 64)
for t in xrange(num_iterations):
# As a regularizer, add random jitter to the image
ox, oy = np.random.randint(-max_jitter, max_jitter + 1, 2)
X = np.roll(np.roll(X, ox, -1), oy, -2)
dX = None
############################################################################
# TODO: Compute the image gradient dX of the image with respect to the #
# target_y class score. This should be similar to the fooling images. Also #
# add L2 regularization to dX and update the image X using the image #
# gradient and the learning rate. #
############################################################################
pass
############################################################################
# END OF YOUR CODE #
############################################################################
# Undo the jitter
X = np.roll(np.roll(X, -ox, -1), -oy, -2)
# As a regularizer, clip the image
X = np.clip(X, -data['mean_image'], 255.0 - data['mean_image'])
# As a regularizer, periodically blur the image
if t % blur_every == 0:
X = blur_image(X)
# Periodically show the image
if t % show_every == 0:
plt.imshow(deprocess_image(X, data['mean_image']))
plt.gcf().set_size_inches(3, 3)
plt.axis('off')
plt.show()
return X
def invert_features(target_feats, layer, model, **kwargs):
"""
Perform feature inversion in the style of Mahendran and Vedaldi 2015, using
L2 regularization and periodic blurring.
Inputs:
- target_feats: Image features of the target image, of shape (1, C, H, W);
we will try to generate an image that matches these features
- layer: The index of the layer from which the features were extracted
- model: A PretrainedCNN that was used to extract features
Keyword arguments:
- learning_rate: The learning rate to use for gradient descent
- num_iterations: The number of iterations to use for gradient descent
- l2_reg: The strength of L2 regularization to use; this is lambda in the
equation above.
- blur_every: How often to blur the image as implicit regularization; set
to 0 to disable blurring.
- show_every: How often to show the generated image; set to 0 to disable
showing intermediate reuslts.
Returns:
- X: Generated image of shape (1, 3, 64, 64) that matches the target features.
"""
learning_rate = kwargs.pop('learning_rate', 10000)
num_iterations = kwargs.pop('num_iterations', 500)
l2_reg = kwargs.pop('l2_reg', 1e-7)
blur_every = kwargs.pop('blur_every', 1)
show_every = kwargs.pop('show_every', 50)
X = np.random.randn(1, 3, 64, 64)
for t in xrange(num_iterations):
############################################################################
# TODO: Compute the image gradient dX of the reconstruction loss with #
# respect to the image. You should include L2 regularization penalizing #
# large pixel values in the generated image using the l2_reg parameter; #
# then update the generated image using the learning_rate from above. #
############################################################################
recons_feats, cache = model.forward(X, end=layer)
dout = -2 * (target_feats - recons_feats)
dX, _ = model.backward(dout, cache)
dX += 2 * l2_reg * X
X -= learning_rate * dX
# As a regularizer, clip the image
X = np.clip(X, -data['mean_image'], 255.0 - data['mean_image'])
# As a regularizer, periodically blur the image
if (blur_every > 0) and t % blur_every == 0:
X = blur_image(X)
if (show_every > 0) and (t % show_every == 0
or t + 1 == num_iterations):
plt.imshow(deprocess_image(X, data['mean_image']))
plt.gcf().set_size_inches(3, 3)
plt.axis('off')
plt.title('t = %d' % t)
plt.show()
def create_class_visualization(target_y, model, **kwargs):
"""
Perform optimization over the image to generate class visualizations.
Inputs:
- target_y: Integer in the range [0, 100) giving the target class
- model: A PretrainedCNN that will be used for generation
Keyword arguments:
- learning_rate: Floating point number giving the learning rate
- blur_every: An integer; how often to blur the image as a regularizer
- l2_reg: Floating point number giving L2 regularization strength on the image; this is lambda in the equation above.
- max_jitter: How much random jitter to add to the image as regularization
- num_iterations: How many iterations to run for
- show_every: How often to show the image
"""
learning_rate = kwargs.pop('learning_rate', 10000)
blur_every = kwargs.pop('blur_every', 1)
l2_reg = kwargs.pop('l2_reg', 1e-6)
max_jitter = kwargs.pop('max_jitter', 4)
num_iterations = kwargs.pop('num_iterations', 100)
show_every = kwargs.pop('show_every', 25)
X = np.random.randn(1, 3, 64, 64)
mode = 'test'
for t in xrange(num_iterations):
# As a regularizer, add random jitter to the image
ox, oy = np.random.randint(-max_jitter, max_jitter+1, 2)
X = np.roll(np.roll(X, ox, -1), oy, -2)
scores, cache = model.forward(X, mode=mode)
class_mask = np.zeros(scores.shape)
class_mask[0,target_y] = 1
scores = scores * class_mask
dX, grads = model.backward(scores, cache)
dX = dX - l2_reg * X
X = X + learning_rate * dX
# Undo the jitter
X = np.roll(np.roll(X, -ox, -1), -oy, -2)
# As a regularizer, clip the image
X = np.clip(X, -data['mean_image'], 255.0 - data['mean_image'])
# As a regularizer, periodically blur the image
if t % blur_every == 0:
X = blur_image(X)
# Periodically show the image
if t % show_every == 0:
plt.imshow(deprocess_image(X, data['mean_image']))
plt.gcf().set_size_inches(3, 3)
plt.axis('off')
img_path = 'images/class_%d_%d.jpg' % (target_y, t)
plt.savefig(img_path)
return X
