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# Copyright (C) 2018 Artsiom Sanakoyeu and Dmytro Kotovenko
#
# This file is part of Adaptive Style Transfer
#
# Adaptive Style Transfer is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Adaptive Style Transfer is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
from __future__ import division
from ops import *
def encoder(image, options, reuse=True, name="encoder"):
"""
Args:
image: input tensor, must have
options: options defining number of kernels in conv layers
reuse: to create new encoder or use existing
name: name of the encoder
Returns: Encoded image.
"""
with tf.variable_scope(name):
if reuse:
tf.get_variable_scope().reuse_variables()
else:
assert tf.get_variable_scope().reuse is False
image = instance_norm(input=image,
is_training=options.is_training,
name='g_e0_bn')
c0 = tf.pad(image, [[0, 0], [15, 15], [15, 15], [0, 0]], "REFLECT")
c1 = tf.nn.relu(instance_norm(input=conv2d(c0, options.gf_dim, 3, 1, padding='VALID', name='g_e1_c'),
is_training=options.is_training,
name='g_e1_bn'))
c2 = tf.nn.relu(instance_norm(input=conv2d(c1, options.gf_dim, 3, 2, padding='VALID', name='g_e2_c'),
is_training=options.is_training,
name='g_e2_bn'))
c3 = tf.nn.relu(instance_norm(conv2d(c2, options.gf_dim * 2, 3, 2, padding='VALID', name='g_e3_c'),
is_training=options.is_training,
name='g_e3_bn'))
c4 = tf.nn.relu(instance_norm(conv2d(c3, options.gf_dim * 4, 3, 2, padding='VALID', name='g_e4_c'),
is_training=options.is_training,
name='g_e4_bn'))
c5 = tf.nn.relu(instance_norm(conv2d(c4, options.gf_dim * 8, 3, 2, padding='VALID', name='g_e5_c'),
is_training=options.is_training,
name='g_e5_bn'))
return c5
def decoder(features, options, reuse=True, name="decoder"):
"""
Args:
features: input tensor, must have
options: options defining number of kernels in conv layers
reuse: to create new decoder or use existing
name: name of the encoder
Returns: Decoded image.
"""
with tf.variable_scope(name):
if reuse:
tf.get_variable_scope().reuse_variables()
else:
assert tf.get_variable_scope().reuse is False
def residule_block(x, dim, ks=3, s=1, name='res'):
p = int((ks - 1) / 2)
y = tf.pad(x, [[0, 0], [p, p], [p, p], [0, 0]], "REFLECT")
y = instance_norm(conv2d(y, dim, ks, s, padding='VALID', name=name+'_c1'), name+'_bn1')
y = tf.pad(tf.nn.relu(y), [[0, 0], [p, p], [p, p], [0, 0]], "REFLECT")
y = instance_norm(conv2d(y, dim, ks, s, padding='VALID', name=name+'_c2'), name+'_bn2')
return y + x
# Now stack 9 residual blocks
num_kernels = features.get_shape().as_list()[-1]
r1 = residule_block(features, num_kernels, name='g_r1')
r2 = residule_block(r1, num_kernels, name='g_r2')
r3 = residule_block(r2, num_kernels, name='g_r3')
r4 = residule_block(r3, num_kernels, name='g_r4')
r5 = residule_block(r4, num_kernels, name='g_r5')
r6 = residule_block(r5, num_kernels, name='g_r6')
r7 = residule_block(r6, num_kernels, name='g_r7')
r8 = residule_block(r7, num_kernels, name='g_r8')
r9 = residule_block(r8, num_kernels, name='g_r9')
# Decode image.
d1 = deconv2d(r9, options.gf_dim * 8, 3, 2, name='g_d1_dc')
d1 = tf.nn.relu(instance_norm(input=d1,
name='g_d1_bn',
is_training=options.is_training))
d2 = deconv2d(d1, options.gf_dim * 4, 3, 2, name='g_d2_dc')
d2 = tf.nn.relu(instance_norm(input=d2,
name='g_d2_bn',
is_training=options.is_training))
d3 = deconv2d(d2, options.gf_dim * 2, 3, 2, name='g_d3_dc')
d3 = tf.nn.relu(instance_norm(input=d3,
name='g_d3_bn',
is_training=options.is_training))
d4 = deconv2d(d3, options.gf_dim, 3, 2, name='g_d4_dc')
d4 = tf.nn.relu(instance_norm(input=d4,
name='g_d4_bn',
is_training=options.is_training))
d4 = tf.pad(d4, [[0, 0], [3, 3], [3, 3], [0, 0]], "REFLECT")
pred = tf.nn.sigmoid(conv2d(d4, 3, 7, 1, padding='VALID', name='g_pred_c'))*2. - 1.
return pred
def discriminator(image, options, reuse=True, name="discriminator"):
"""
Discriminator agent, that provides us with information about image plausibility at
different scales.
Args:
image: input tensor
options: options defining number of kernels in conv layers
reuse: to create new discriminator or use existing
name: name of the discriminator
Returns:
Image estimates at different scales.
"""
with tf.variable_scope(name):
if reuse:
tf.get_variable_scope().reuse_variables()
else:
assert tf.get_variable_scope().reuse is False
h0 = lrelu(instance_norm(conv2d(image, options.df_dim * 2, ks=5, name='d_h0_conv'),
name='d_bn0'))
h0_pred = conv2d(h0, 1, ks=5, s=1, name='d_h0_pred', activation_fn=None)
h1 = lrelu(instance_norm(conv2d(h0, options.df_dim * 2, ks=5, name='d_h1_conv'),
name='d_bn1'))
h1_pred = conv2d(h1, 1, ks=10, s=1, name='d_h1_pred', activation_fn=None)
h2 = lrelu(instance_norm(conv2d(h1, options.df_dim * 4, ks=5, name='d_h2_conv'),
name='d_bn2'))
h3 = lrelu(instance_norm(conv2d(h2, options.df_dim * 8, ks=5, name='d_h3_conv'),
name='d_bn3'))
h3_pred = conv2d(h3, 1, ks=10, s=1, name='d_h3_pred', activation_fn=None)
h4 = lrelu(instance_norm(conv2d(h3, options.df_dim * 8, ks=5, name='d_h4_conv'),
name='d_bn4'))
h5 = lrelu(instance_norm(conv2d(h4, options.df_dim * 16, ks=5, name='d_h5_conv'),
name='d_bn5'))
h5_pred = conv2d(h5, 1, ks=6, s=1, name='d_h5_pred', activation_fn=None)
h6 = lrelu(instance_norm(conv2d(h5, options.df_dim * 16, ks=5, name='d_h6_conv'),
name='d_bn6'))
h6_pred = conv2d(h6, 1, ks=3, s=1, name='d_h6_pred', activation_fn=None)
return {"scale_0": h0_pred,
"scale_1": h1_pred,
"scale_3": h3_pred,
"scale_5": h5_pred,
"scale_6": h6_pred}
# ====== Define different types of losses applied to discriminator's output. ====== #
def abs_criterion(in_, target):
return tf.reduce_mean(tf.abs(in_ - target))
def mae_criterion(in_, target):
return tf.reduce_mean(tf.abs(in_-target))
def mse_criterion(in_, target):
return tf.reduce_mean((in_-target)**2)
def sce_criterion(logits, labels):
return tf.reduce_mean(tf.nn.sigmoid_cross_entropy_with_logits(logits=logits, labels=labels))
def reduce_spatial_dim(input_tensor):
"""
Since labels and discriminator outputs are of different shapes (and even ranks)
we should write a routine to deal with that.
Args:
input: tensor of shape [batch_size, spatial_resol_1, spatial_resol_2, depth]
Returns:
tensor of shape [batch_size, depth]
"""
input_tensor = tf.reduce_mean(input_tensor=input_tensor, axis=1)
input_tensor = tf.reduce_mean(input_tensor=input_tensor, axis=1)
return input_tensor
def add_spatial_dim(input_tensor, dims_list, resol_list):
"""
Appends dimensions mentioned in dims_list resol_list times. S
Args:
input: tensor of shape [batch_size, depth0]
dims_list: list of integers with position of new dimensions to append.
resol_list: list of integers with corresponding new dimensionalities for each dimension.
Returns:
tensor of new shape
"""
for dim, res in zip(dims_list, resol_list):
input_tensor = tf.expand_dims(input=input_tensor, axis=dim)
input_tensor = tf.concat(values=[input_tensor]*res, axis=dim)
return input_tensor
def repeat_scalar(input_tensor, shape):
"""
Repeat scalar values.
:param input_tensor: tensor of shape [batch_size, 1]
:param shape: new_shape of the element of the tensor
:return: tensor of the shape [batch_size, *shape] with elements repeated.
"""
with tf.control_dependencies([tf.assert_equal(tf.shape(input_tensor)[1], 1)]):
batch_size = tf.shape(input_tensor)[0]
input_tensor = tf.tile(input_tensor, tf.stack(values=[1, tf.reduce_prod(shape)], axis=0))
input_tensor = tf.reshape(input_tensor, tf.concat(values=[[batch_size], shape, [1]], axis=0))
return input_tensor
def transformer_block(input_tensor, kernel_size=10):
"""
This is a simplified version of transformer block described in our paper
https://arxiv.org/abs/1807.10201.
Args:
input_tensor: Image(or tensor of rank 4) we want to transform.
kernel_size: Size of kernel we apply to the input_tensor.
Returns:
Transformed tensor
"""
return slim.avg_pool2d(inputs=input_tensor, kernel_size=kernel_size, stride=1, padding='SAME')
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