pix2pixhd

Pix2Pix HD Implementation See: “High-Resolution Image Synthesis and Semantic Manipulation with Conditional GANs” 1

Global Generator + Local Enhancer

1

High-Resolution Image Synthesis and Semantic Manipulation with Conditional GANs: https://arxiv.org/abs/1711.11585

Classes

GlobalGenerator	Global Generator from pix2pixHD paper:
LocalEnhancer	Local Enhancer module of the Pix2PixHD architecture.
ResNetBlock	ResNet Blocks: the input filters is the same as the output filters.

class ashpy.models.convolutional.pix2pixhd.GlobalGenerator(input_res=512, min_res=64, initial_filters=64, filters_cap=512, channels=3, normalization_layer=<class 'ashpy.layers.instance_normalization.InstanceNormalization'>, non_linearity=<class 'tensorflow.python.keras.layers.advanced_activations.ReLU'>, num_resnet_blocks=9, kernel_size_resnet=3, kernel_size_front_back=7, num_internal_resnet_blocks=2)

Bases: ashpy.models.convolutional.interfaces.Conv2DInterface

Global Generator from pix2pixHD paper:

• G1^F: Convolutional frontend (downsampling)

• G1^R: ResNet Block

• G1^B: Convolutional backend (upsampling)

__init__(input_res=512, min_res=64, initial_filters=64, filters_cap=512, channels=3, normalization_layer=<class 'ashpy.layers.instance_normalization.InstanceNormalization'>, non_linearity=<class 'tensorflow.python.keras.layers.advanced_activations.ReLU'>, num_resnet_blocks=9, kernel_size_resnet=3, kernel_size_front_back=7, num_internal_resnet_blocks=2)

Global Generator from Pix2PixHD

Parameters

• input_res (int) – Input Resolution

• min_res (int) – Minimum resolution reached by the downsampling

• initial_filters (int) – number of initial filters

• filters_cap (int) – maximum number of filters

• channels (int) – output channels

• normalization_layer (tf.keras.layers.Layer) – normalization layer used by the global generator, can be Instance Norm, Layer Norm, Batch Norm

• non_linearity (tf.keras.layers.Layer) – non linearity used in the global generator

• num_resnet_blocks (int) – number of resnet blocks

• kernel_size_resnet (int) – kernel size used in resnets conv layers

• kernel_size_front_back (int) – kernel size used by the convolutional frontend and backend

• num_internal_resnet_blocks (int) – number of blocks used by internal resnet

call(inputs, training=True)

Call of the Pix2Pix HD model :param inputs: input tensor(s) :param training: If True training phase

Returns

Tuple – Generated images.

class ashpy.models.convolutional.pix2pixhd.LocalEnhancer(input_res=512, min_res=64, initial_filters=64, filters_cap=512, channels=3, normalization_layer=<class 'ashpy.layers.instance_normalization.InstanceNormalization'>, non_linearity=<class 'tensorflow.python.keras.layers.advanced_activations.ReLU'>, num_resnet_blocks_global=9, num_resnet_blocks_local=3, kernel_size_resnet=3, kernel_size_front_back=7, num_internal_resnet_blocks=2)

Bases: tensorflow.python.keras.engine.training.Model

Local Enhancer module of the Pix2PixHD architecture.

Example

# instantiate the model
model = LocalEnhancer()

# call the model passing inputs
inputs = tf.ones((1, 512, 512, 3))
output = model(inputs)

# the output shape is
# the same as the input shape
print(output.shape)

(1, 512, 512, 3)

__init__(input_res=512, min_res=64, initial_filters=64, filters_cap=512, channels=3, normalization_layer=<class 'ashpy.layers.instance_normalization.InstanceNormalization'>, non_linearity=<class 'tensorflow.python.keras.layers.advanced_activations.ReLU'>, num_resnet_blocks_global=9, num_resnet_blocks_local=3, kernel_size_resnet=3, kernel_size_front_back=7, num_internal_resnet_blocks=2)

Build the LocalEnhancer module of the Pix2PixHD architecture.

See High-Resolution Image Synthesis and Semantic Manipulation with Conditional GANs 2 for more details.

Parameters

• input_res (int) – input resolution

• min_res (int) – minimum resolution reached by the global generator

• initial_filters (int) – number of initial filters

• filters_cap (int) – maximum number of filters

• channels (int) – number of channels

• normalization_layer (tf.keras.layers.Layer) – layer of normalization

• Instance Normalization or BatchNormalization or LayerNormalization) ((e.g.) –

• non_linearity (tf.keras.layers.Layer) – non linearity used in Pix2Pix HD

• num_resnet_blocks_global (int) – number of residual blocks used in the global generator

• num_resnet_blocks_local (int) – number of residual blocks used in the local generator

• kernel_size_resnet (int) – kernel size used in resnets

• kernel_size_front_back (int) – kernel size used for the front and back convolution

• num_internal_resnet_blocks (int) – number of internal blocks of the resnet

2

High-Resolution Image Synthesis and Semantic Manipulation with Conditional GANs https://arxiv.org/abs/1711.11585

call(inputs, training=False)

LocalEnhancer call. :param inputs: Input Tensors :type inputs: tf.Tensor :param training: Whether it is training phase or not :type training: bool

Returns

(tf.Tensor) –

Image of size (input_res, input_res, channels)

as specified in the init call

class ashpy.models.convolutional.pix2pixhd.ResNetBlock(filters, normalization_layer=<class 'ashpy.layers.instance_normalization.InstanceNormalization'>, non_linearity=<class 'tensorflow.python.keras.layers.advanced_activations.ReLU'>, kernel_size=3, num_blocks=2)

Bases: tensorflow.python.keras.engine.training.Model

ResNet Blocks: the input filters is the same as the output filters.

__init__(filters, normalization_layer=<class 'ashpy.layers.instance_normalization.InstanceNormalization'>, non_linearity=<class 'tensorflow.python.keras.layers.advanced_activations.ReLU'>, kernel_size=3, num_blocks=2)

ResNet block composed by num_blocks. Each block is composed by

• Conv2D with strides 1 and padding “same”

• Normalization Layer

• Non Linearity

The final result is the output of the ResNet + input

Parameters

• filters (int) – initial filters (same as the output filters)

• normalization_layer (tf.keras.layers.Layer) – layer of normalization used by the residual block

• non_linearity (tf.keras.layers.Layer) – non linearity used in the resnet block

• kernel_size (int) – kernel size used in the resnet block

• num_blocks (int) – number of blocks, each block is composed by conv, normalization and non linearity

call(inputs, training=False)

Forward pass :param inputs: input tensor :param training: whether is training or not

Returns

A Tensor of the same shape as the inputs. The input passed through num_blocks blocks.