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Contributions

In now, this repo contains general architectures and functions that are useful for the GAN and classificstion.

I will continue to add useful things to other areas.

Also, your pull requests and issues are always welcome.

And write what you want to implement on the issue. I'll implement it.

How to use

Import

• ops.py
  • operations
  • from ops import *
• utils.py
  • image processing
  • from utils import *

Network template

def network(x, is_training=True, reuse=False, scope="network"):
    with tf.variable_scope(scope, reuse=reuse):
        x = conv(...)
        
        ...
        
        return logit

Insert data to network using DatasetAPI

Image_Data_Class = ImageData(img_size, img_ch, augment_flag)

trainA_dataset = ['./dataset/cat/trainA/a.jpg', 
                  './dataset/cat/trainA/b.png', 
                  './dataset/cat/trainA/c.jpeg', 
                  ...]
trainA = tf.data.Dataset.from_tensor_slices(trainA_dataset)
trainA = trainA.map(Image_Data_Class.image_processing, num_parallel_calls=16)
trainA = trainA.shuffle(buffer_size=10000).prefetch(buffer_size=batch_size).batch(batch_size).repeat()

trainA_iterator = trainA.make_one_shot_iterator()
data_A = trainA_iterator.get_next()

logit = network(data_A)

• See this for more information.

Option

• padding='SAME'
  • pad = ceil[ (kernel - stride) / 2 ]
• pad_type
  • 'zero' or 'reflect'
• sn
  • use spectral_normalization or not

Caution

• If you don't want to share variable, set all scope names differently.

---

Weight

weight_init = tf.truncated_normal_initializer(mean=0.0, stddev=0.02)
weight_regularizer = tf.contrib.layers.l2_regularizer(0.0001)
weight_regularizer_fully = tf.contrib.layers.l2_regularizer(0.0001)

Initialization

• Xavier : tf.contrib.layers.xavier_initializer()
• He : tf.contrib.layers.variance_scaling_initializer()
• Normal : tf.random_normal_initializer(mean=0.0, stddev=0.02)
• Truncated_normal : tf.truncated_normal_initializer(mean=0.0, stddev=0.02)
• Orthogonal : tf.orthogonal_initializer(1.0) / # if relu = sqrt(2), the others = 1.0

Regularization

• l2_decay : tf.contrib.layers.l2_regularizer(0.0001)
• orthogonal_regularizer : orthogonal_regularizer(0.0001) & orthogonal_regularizer_fully(0.0001)

Convolution

basic conv

x = conv(x, channels=64, kernel=3, stride=2, pad=1, pad_type='reflect', use_bias=True, sn=True, scope='conv')

partial conv (NVIDIA Partial Convolution)

x = partial_conv(x, channels=64, kernel=3, stride=2, use_bias=True, padding='SAME', sn=True, scope='partial_conv')

dilated conv

x = dilate_conv(x, channels=64, kernel=3, rate=2, use_bias=True, padding='VALID', sn=True, scope='dilate_conv')

---

Deconvolution

basic deconv

x = deconv(x, channels=64, kernel=3, stride=1, padding='SAME', use_bias=True, sn=True, scope='deconv')

---

Fully-connected

x = fully_conneted(x, units=64, use_bias=True, sn=True, scope='fully_connected')

---

Pixel shuffle

x = conv_pixel_shuffle_down(x, scale_factor=2, use_bias=True, sn=True, scope='pixel_shuffle_down')
x = conv_pixel_shuffle_up(x, scale_factor=2, use_bias=True, sn=True, scope='pixel_shuffle_up')

• down ===> [height, width] -> [height // scale_factor, width // scale_factor]
• up ===> [height, width] -> [height * scale_factor, width * scale_factor]

---

Block

residual block

x = resblock(x, channels=64, is_training=is_training, use_bias=True, sn=True, scope='residual_block')
x = resblock_down(x, channels=64, is_training=is_training, use_bias=True, sn=True, scope='residual_block_down')
x = resblock_up(x, channels=64, is_training=is_training, use_bias=True, sn=True, scope='residual_block_up')

• down ===> [height, width] -> [height // 2, width // 2]
• up ===> [height, width] -> [height * 2, width * 2]

dense block

x = denseblock(x, channels=64, n_db=6, is_training=is_training, use_bias=True, sn=True, scope='denseblock')

• n_db ===> The number of dense-block

residual-dense block

x = res_denseblock(x, channels=64, n_rdb=20, n_rdb_conv=6, is_training=is_training, use_bias=True, sn=True, scope='res_denseblock')

• n_rdb ===> The number of RDB
• n_rdb_conv ===> per RDB conv layer

attention block

x = self_attention(x, channels=64, use_bias=True, sn=True, scope='self_attention')
x = self_attention_with_pooling(x, channels=64, use_bias=True, sn=True, scope='self_attention_version_2')

x = squeeze_excitation(x, channels=64, ratio=16, use_bias=True, sn=True, scope='squeeze_excitation')

x = convolution_block_attention(x, channels=64, ratio=16, use_bias=True, sn=True, scope='convolution_block_attention')

---

---

---

Normalization

x = batch_norm(x, is_training=is_training, scope='batch_norm')
x = layer_norm(x, scope='layer_norm')
x = instance_norm(x, scope='instance_norm')
x = group_norm(x, groups=32, scope='group_norm')

x = pixel_norm(x)

x = batch_instance_norm(x, scope='batch_instance_norm')
x = switch_norm(x, scope='switch_norm')

x = condition_batch_norm(x, z, is_training=is_training, scope='condition_batch_norm'):

x = adaptive_instance_norm(x, gamma, beta)

• See this for how to use condition_batch_norm
• See this for how to use adaptive_instance_norm

---

Activation

x = relu(x)
x = lrelu(x, alpha=0.2)
x = tanh(x)
x = sigmoid(x)
x = swish(x)

---

Pooling & Resize

x = up_sample(x, scale_factor=2)

x = max_pooling(x, pool_size=2)
x = avg_pooling(x, pool_size=2)

x = global_max_pooling(x)
x = global_avg_pooling(x)

x = flatten(x)
x = hw_flatten(x)

---

Loss

classification loss

loss, accuracy = classification_loss(logit, label)

pixel loss

loss = L1_loss(x, y)
loss = L2_loss(x, y)
loss = huber_loss(x, y)
loss = histogram_loss(x, y)

• histogram_loss means the difference in the color distribution of the image pixel values.

gan loss

d_loss = discriminator_loss(Ra=True, loss_func='wgan-gp', real=real_logit, fake=fake_logit)
g_loss = generator_loss(Ra=True, loss_func='wgan-gp', real=real_logit, fake=fake_logit)

• Ra
  • use relativistic gan or not
• loss_func
  • gan
  • lsgan
  • hinge
  • wgan
  • wgan-gp
  • dragan
• See this for how to use gradient_penalty

vdb loss

d_bottleneck_loss = vdb_loss(real_mu, real_logvar, i_c) + vdb_loss(fake_mu, fake_logvar, i_c)

kl-divergence (z ~ N(0, 1))

loss = kl_loss(mean, logvar)

---

Author

Junho Kim