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faceswap/lib/model/initializers.py
torzdf 5418fba726
Add Convolutional Aware Initialization (#795)
* Training: Add Convolutional Aware Initialization config option

* Centralize Conv2D layer for handling initializer

* Add 'is-output' to NNMeta to indicate that network is an output to the Model
2019-07-16 10:09:29 +01:00

207 lines
7.5 KiB
Python

#!/usr/bin/env python3
""" Custom Initializers for faceswap.py
Initializers from:
shoanlu GAN: https://github.com/shaoanlu/faceswap-GAN"""
import logging
import sys
import inspect
import numpy as np
import tensorflow as tf
from keras import backend as K
from keras import initializers
from keras.utils.generic_utils import get_custom_objects
logger = logging.getLogger(__name__) # pylint: disable=invalid-name
def icnr_keras(shape, dtype=None):
"""
Custom initializer for subpix upscaling
From https://github.com/kostyaev/ICNR
Note: upscale factor is fixed to 2, and the base initializer is fixed to random normal.
"""
# TODO Roll this into ICNR_init when porting GAN 2.2
shape = list(shape)
scale = 2
initializer = tf.keras.initializers.RandomNormal(0, 0.02)
new_shape = shape[:3] + [int(shape[3] / (scale ** 2))]
var_x = initializer(new_shape, dtype)
var_x = tf.transpose(var_x, perm=[2, 0, 1, 3])
var_x = tf.image.resize_nearest_neighbor(var_x, size=(shape[0] * scale, shape[1] * scale))
var_x = tf.space_to_depth(var_x, block_size=scale)
var_x = tf.transpose(var_x, perm=[1, 2, 0, 3])
return var_x
class ICNR(initializers.Initializer): # pylint: disable=invalid-name
'''
ICNR initializer for checkerboard artifact free sub pixel convolution
Andrew Aitken et al. Checkerboard artifact free sub-pixel convolution
https://arxiv.org/pdf/1707.02937.pdf https://distill.pub/2016/deconv-checkerboard/
Parameters:
initializer: initializer used for sub kernels (orthogonal, glorot uniform, etc.)
scale: scale factor of sub pixel convolution (upsampling from 8x8 to 16x16 is scale 2)
Return:
The modified kernel weights
Example:
x = conv2d(... weights_initializer=ICNR(initializer=he_uniform(), scale=2))
'''
def __init__(self, initializer, scale=2):
self.scale = scale
self.initializer = initializer
def __call__(self, shape, dtype='float32'): # tf needs partition_info=None
shape = list(shape)
if self.scale == 1:
return self.initializer(shape)
new_shape = shape[:3] + [shape[3] // (self.scale ** 2)]
if isinstance(self.initializer, dict):
self.initializer = initializers.deserialize(self.initializer)
var_x = self.initializer(new_shape, dtype)
var_x = tf.transpose(var_x, perm=[2, 0, 1, 3])
var_x = tf.image.resize_nearest_neighbor(
var_x,
size=(shape[0] * self.scale, shape[1] * self.scale),
align_corners=True)
var_x = tf.space_to_depth(var_x, block_size=self.scale, data_format='NHWC')
var_x = tf.transpose(var_x, perm=[1, 2, 0, 3])
return var_x
def get_config(self):
config = {'scale': self.scale,
'initializer': self.initializer
}
base_config = super(ICNR, self).get_config()
return dict(list(base_config.items()) + list(config.items()))
class ConvolutionAware(initializers.Initializer):
"""
Initializer that generates orthogonal convolution filters in the fourier
space. If this initializer is passed a shape that is not 3D or 4D,
orthogonal initialization will be used.
# Arguments
eps_std: Standard deviation for the random normal noise used to break
symmetry in the inverse fourier transform.
seed: A Python integer. Used to seed the random generator.
# References
Armen Aghajanyan, https://arxiv.org/abs/1702.06295
# Adapted and fixed from:
https://github.com/keras-team/keras-contrib/blob/master/keras_contrib/initializers/convaware.py
"""
def __init__(self, eps_std=0.05, seed=None, init=False):
# Convolutional Aware Initialization takes a long time.
# Keras model loading loads a model, performs initialization and then
# loads weights, which is an unnecessary waste of time.
# init defaults to False so that this is bypassed when loading a saved model
# passing zeros
self._init = init
self.eps_std = eps_std
self.seed = seed
self.orthogonal = initializers.Orthogonal()
self.he_uniform = initializers.he_uniform()
def __call__(self, shape, dtype=None):
dtype = K.floatx() if dtype is None else dtype
if self._init:
logger.info("Calculating Convolution Aware Initializer for shape: %s", shape)
else:
logger.debug("Bypassing Convolutional Aware Initializer for saved model")
# Dummy in he_uniform just in case there aren't any weighs being loaded
# and it needs some kind of initialization
return self.he_uniform(shape, dtype=dtype)
rank = len(shape)
if self.seed is not None:
np.random.seed(self.seed)
fan_in, _ = initializers._compute_fans(shape) # pylint:disable=protected-access
variance = 2 / fan_in
if rank == 3:
row, stack_size, filters_size = shape
transpose_dimensions = (2, 1, 0)
kernel_shape = (row,)
correct_ifft = lambda shape, s=[None]: np.fft.irfft(shape, s[0]) # noqa
correct_fft = np.fft.rfft
elif rank == 4:
row, column, stack_size, filters_size = shape
transpose_dimensions = (2, 3, 1, 0)
kernel_shape = (row, column)
correct_ifft = np.fft.irfft2
correct_fft = np.fft.rfft2
elif rank == 5:
var_x, var_y, var_z, stack_size, filters_size = shape
transpose_dimensions = (3, 4, 0, 1, 2)
kernel_shape = (var_x, var_y, var_z)
correct_fft = np.fft.rfftn
correct_ifft = np.fft.irfftn
else:
return K.variable(self.orthogonal(shape), dtype=dtype)
kernel_fourier_shape = correct_fft(np.zeros(kernel_shape)).shape
init = []
for _ in range(filters_size):
basis = self._create_basis(
stack_size, np.prod(kernel_fourier_shape), dtype)
basis = basis.reshape((stack_size,) + kernel_fourier_shape)
filters = [correct_ifft(x, kernel_shape) +
np.random.normal(0, self.eps_std, kernel_shape) for
x in basis]
init.append(filters)
# Format of array is now: filters, stack, row, column
init = np.array(init)
init = self._scale_filters(init, variance)
return K.variable(init.transpose(transpose_dimensions), dtype=dtype, name="conv_aware")
def _create_basis(self, filters, size, dtype):
if size == 1:
return np.random.normal(0.0, self.eps_std, (filters, size))
nbb = filters // size + 1
lst = []
for _ in range(nbb):
var_a = np.random.normal(0.0, 1.0, (size, size))
var_a = self._symmetrize(var_a)
var_u, _, _ = np.linalg.svd(var_a)
lst.extend(var_u.T.tolist())
var_p = np.array(lst[:filters], dtype=dtype)
return var_p
@staticmethod
def _symmetrize(var_a):
return var_a + var_a.T - np.diag(var_a.diagonal())
@staticmethod
def _scale_filters(filters, variance):
c_var = np.var(filters)
var_p = np.sqrt(variance / c_var)
return filters * var_p
def get_config(self):
return {
'eps_std': self.eps_std,
'seed': self.seed
}
# Update initializers into Keras custom objects
for name, obj in inspect.getmembers(sys.modules[__name__]):
if inspect.isclass(obj) and obj.__module__ == __name__:
get_custom_objects().update({name: obj})