def train_decoder(self, layer_name):
decoder = self.observed_layers[layer_name]['decoder']
n_epochs = self.observed_layers[layer_name]['n_epochs']
learning_rate = self.observed_layers[layer_name].get(
'learning_rate', 1e-3)
training_loss_values = []
image_loss = nn.MSELoss()
optimizer = torch.optim.Adam(decoder.parameters(), lr=learning_rate)
for epoch_index in range(n_epochs):
#print(f'Epoch {epoch_index}')
epoch_loss = 0
# reconstruct
self.encoder(vgg_normalization(self.source_tensor).unsqueeze(0))
embedding = self.encoder_layers[layer_name]
generated_tensor = decoder(embedding).squeeze()
# re-embed
self.encoder(vgg_normalization(generated_tensor).unsqueeze(0))
generated_embedding = self.encoder_layers[layer_name]
loss = image_loss(self.source_tensor, generated_tensor) + \
torch.norm(embedding - generated_embedding)
optimizer.zero_grad()
loss.backward()
optimizer.step()
epoch_loss += loss
training_loss_values.append(epoch_loss)
return training_loss_values
def __init__(self, source_image, observed_layers, n_bins=128):
"""
:param source_image: source image
:type image: PIL Image object
:param observed_layers: dictionary containing layer-specific information ; see bottom of file decoders.py
:type observed_layers: dictionary
:param n_bins: number of transportation histogram bins, defaults to 128 [TO BE IMPLEMENTED]
:type n_bins: int, optional
"""
# source image
self.source_tensor = image_preprocessing(source_image)
self.normalized_source_batch = vgg_normalization(
self.source_tensor).unsqueeze(0)
self.source_batch = self.source_tensor.unsqueeze(0)
# set encoder
self.encoder = vgg19(pretrained=True).float()
self.encoder.eval()
for param in self.encoder.features.parameters():
param.requires_grad = False
self.encoder_layers = {}
self.set_encoder_hooks(observed_layers)
self.n_bins = n_bins
def __init__(self, style_image, content_image, observed_layers, n_bins=128, decoder_weights_path=None):
super().__init__(style_image, observed_layers, n_bins=n_bins)
# input image
self.content_tensor = image_preprocessing(content_image)
self.normalized_content_batch = vgg_normalization(
self.content_tensor).unsqueeze(0)
self.content_batch = self.content_tensor.unsqueeze(0)
def transfer(self, n_passes=5, content_strength=0.5):
"""Style transfer
:param n_passes: number of global passes, defaults to 5
:type n_passes: int, optional
:param content_strength: content strength, defaults to 0.5
:type content_strength: float, optional
:return: generated images layer by layer, step by step
:rtype: list
"""
self.n_passes = n_passes
pass_generated_images = []
# initialize with noise
self.target_tensor = torch.randn_like(self.source_tensor)
for global_pass in range(n_passes):
print(f'global pass {global_pass}')
for layer_name, layer_information in self.observed_layers.items():
print(f'layer {layer_name}')
# forward pass on source image
self.encoder(self.normalized_source_batch)
source_layer = self.encoder_layers[layer_name]
# forward pass on content image
self.encoder(self.normalized_content_batch)
content_layer = self.encoder_layers[layer_name]
# forward pass on target image
target_batch = vgg_normalization(
self.target_tensor).unsqueeze(0)
self.encoder(target_batch)
target_layer = self.encoder_layers[layer_name]
# transport
target_layer = self.optimal_transport(layer_name,
source_layer.squeeze(),
target_layer.squeeze())
target_layer = target_layer.view_as(source_layer)
# feature style transfer
target_layer += content_strength * \
(content_layer - target_layer)
# decode
decoder = layer_information['decoder']
self.target_tensor = decoder(target_layer).squeeze()
generated_image = np.transpose(self.target_tensor.numpy(),
(1, 2, 0)).copy()
pass_generated_images.append(generated_image)
return pass_generated_images
def __init__(self,
style_image,
content_image,
observed_layers,
n_bins=128):
"""
:param content_image: content image
:type content_image: PIL Image object
"""
super().__init__(style_image, observed_layers, n_bins=n_bins)
# input image
self.content_tensor = image_preprocessing(content_image)
self.normalized_content_batch = vgg_normalization(
self.content_tensor).unsqueeze(0)
self.content_batch = self.content_tensor.unsqueeze(0)
def __init__(self, image, observed_layers, n_bins=128):
# source image
self.source_tensor = image_preprocessing(image)
self.normalized_source_batch = vgg_normalization(
self.source_tensor).unsqueeze(0)
self.source_batch = self.source_tensor.unsqueeze(0)
# set encoder
self.encoder = vgg19(pretrained=True).float()
self.encoder.eval()
for param in self.encoder.features.parameters():
param.requires_grad = False
self.encoder_layers = {}
self.set_encoder_hooks(observed_layers)
self.n_bins = n_bins
def generate(self, n_passes=5):
self.n_passes = n_passes
pass_generated_images = []
# initialize with noise
self.target_tensor = torch.randn_like(self.source_tensor)
for global_pass in range(n_passes):
print(f'global pass {global_pass}')
for layer_name, layer_information in self.observed_layers.items():
print(f'layer {layer_name}')
# forward pass on source image
self.encoder(self.normalized_source_batch)
source_layer = self.encoder_layers[layer_name]
# forward pass on target image
target_batch = vgg_normalization(
self.target_tensor).unsqueeze(0)
self.encoder(target_batch)
target_layer = self.encoder_layers[layer_name]
# transport
target_layer = self.optimal_transport(layer_name,
source_layer.squeeze(),
target_layer.squeeze())
target_layer = target_layer.view_as(source_layer)
# decode
decoder = layer_information['decoder']
self.target_tensor = decoder(target_layer).squeeze()
generated_image = np.transpose(self.target_tensor.numpy(),
(1, 2, 0)).copy()
pass_generated_images.append(generated_image)
return pass_generated_images