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from functools import partial | |
import numpy as np | |
import torch | |
from timm.models.efficientnet import tf_efficientnet_b4_ns, tf_efficientnet_b3_ns, \ | |
tf_efficientnet_b5_ns, tf_efficientnet_b2_ns, tf_efficientnet_b6_ns, tf_efficientnet_b7_ns | |
from torch import nn | |
from torch.nn.modules.dropout import Dropout | |
from torch.nn.modules.linear import Linear | |
from torch.nn.modules.pooling import AdaptiveAvgPool2d | |
encoder_params = { | |
"tf_efficientnet_b3_ns": { | |
"features": 1536, | |
"init_op": partial(tf_efficientnet_b3_ns, pretrained=True, drop_path_rate=0.2) | |
}, | |
"tf_efficientnet_b2_ns": { | |
"features": 1408, | |
"init_op": partial(tf_efficientnet_b2_ns, pretrained=False, drop_path_rate=0.2) | |
}, | |
"tf_efficientnet_b4_ns": { | |
"features": 1792, | |
"init_op": partial(tf_efficientnet_b4_ns, pretrained=True, drop_path_rate=0.5) | |
}, | |
"tf_efficientnet_b5_ns": { | |
"features": 2048, | |
"init_op": partial(tf_efficientnet_b5_ns, pretrained=True, drop_path_rate=0.2) | |
}, | |
"tf_efficientnet_b4_ns_03d": { | |
"features": 1792, | |
"init_op": partial(tf_efficientnet_b4_ns, pretrained=True, drop_path_rate=0.3) | |
}, | |
"tf_efficientnet_b5_ns_03d": { | |
"features": 2048, | |
"init_op": partial(tf_efficientnet_b5_ns, pretrained=True, drop_path_rate=0.3) | |
}, | |
"tf_efficientnet_b5_ns_04d": { | |
"features": 2048, | |
"init_op": partial(tf_efficientnet_b5_ns, pretrained=True, drop_path_rate=0.4) | |
}, | |
"tf_efficientnet_b6_ns": { | |
"features": 2304, | |
"init_op": partial(tf_efficientnet_b6_ns, pretrained=True, drop_path_rate=0.2) | |
}, | |
"tf_efficientnet_b7_ns": { | |
"features": 2560, | |
"init_op": partial(tf_efficientnet_b7_ns, pretrained=True, drop_path_rate=0.2) | |
}, | |
"tf_efficientnet_b6_ns_04d": { | |
"features": 2304, | |
"init_op": partial(tf_efficientnet_b6_ns, pretrained=True, drop_path_rate=0.4) | |
}, | |
} | |
def setup_srm_weights(input_channels: int = 3) -> torch.Tensor: | |
"""Creates the SRM kernels for noise analysis.""" | |
# note: values taken from Zhou et al., "Learning Rich Features for Image Manipulation Detection", CVPR2018 | |
srm_kernel = torch.from_numpy(np.array([ | |
[ # srm 1/2 horiz | |
[0., 0., 0., 0., 0.], # noqa: E241,E201 | |
[0., 0., 0., 0., 0.], # noqa: E241,E201 | |
[0., 1., -2., 1., 0.], # noqa: E241,E201 | |
[0., 0., 0., 0., 0.], # noqa: E241,E201 | |
[0., 0., 0., 0., 0.], # noqa: E241,E201 | |
], [ # srm 1/4 | |
[0., 0., 0., 0., 0.], # noqa: E241,E201 | |
[0., -1., 2., -1., 0.], # noqa: E241,E201 | |
[0., 2., -4., 2., 0.], # noqa: E241,E201 | |
[0., -1., 2., -1., 0.], # noqa: E241,E201 | |
[0., 0., 0., 0., 0.], # noqa: E241,E201 | |
], [ # srm 1/12 | |
[-1., 2., -2., 2., -1.], # noqa: E241,E201 | |
[2., -6., 8., -6., 2.], # noqa: E241,E201 | |
[-2., 8., -12., 8., -2.], # noqa: E241,E201 | |
[2., -6., 8., -6., 2.], # noqa: E241,E201 | |
[-1., 2., -2., 2., -1.], # noqa: E241,E201 | |
] | |
])).float() | |
srm_kernel[0] /= 2 | |
srm_kernel[1] /= 4 | |
srm_kernel[2] /= 12 | |
return srm_kernel.view(3, 1, 5, 5).repeat(1, input_channels, 1, 1) | |
def setup_srm_layer(input_channels: int = 3) -> torch.nn.Module: | |
"""Creates a SRM convolution layer for noise analysis.""" | |
weights = setup_srm_weights(input_channels) | |
conv = torch.nn.Conv2d(input_channels, out_channels=3, kernel_size=5, stride=1, padding=2, bias=False) | |
with torch.no_grad(): | |
conv.weight = torch.nn.Parameter(weights, requires_grad=False) | |
return conv | |
class DeepFakeClassifierSRM(nn.Module): | |
def __init__(self, encoder, dropout_rate=0.5) -> None: | |
super().__init__() | |
self.encoder = encoder_params[encoder]["init_op"]() | |
self.avg_pool = AdaptiveAvgPool2d((1, 1)) | |
self.srm_conv = setup_srm_layer(3) | |
self.dropout = Dropout(dropout_rate) | |
self.fc = Linear(encoder_params[encoder]["features"], 1) | |
def forward(self, x): | |
noise = self.srm_conv(x) | |
x = self.encoder.forward_features(noise) | |
x = self.avg_pool(x).flatten(1) | |
x = self.dropout(x) | |
x = self.fc(x) | |
return x | |
class GlobalWeightedAvgPool2d(nn.Module): | |
""" | |
Global Weighted Average Pooling from paper "Global Weighted Average | |
Pooling Bridges Pixel-level Localization and Image-level Classification" | |
""" | |
def __init__(self, features: int, flatten=False): | |
super().__init__() | |
self.conv = nn.Conv2d(features, 1, kernel_size=1, bias=True) | |
self.flatten = flatten | |
def fscore(self, x): | |
m = self.conv(x) | |
m = m.sigmoid().exp() | |
return m | |
def norm(self, x: torch.Tensor): | |
return x / x.sum(dim=[2, 3], keepdim=True) | |
def forward(self, x): | |
input_x = x | |
x = self.fscore(x) | |
x = self.norm(x) | |
x = x * input_x | |
x = x.sum(dim=[2, 3], keepdim=not self.flatten) | |
return x | |
class DeepFakeClassifier(nn.Module): | |
def __init__(self, encoder, dropout_rate=0.0) -> None: | |
super().__init__() | |
self.encoder = encoder_params[encoder]["init_op"]() | |
self.avg_pool = AdaptiveAvgPool2d((1, 1)) | |
self.dropout = Dropout(dropout_rate) | |
self.fc = Linear(encoder_params[encoder]["features"], 1) | |
def forward(self, x): | |
x = self.encoder.forward_features(x) | |
x = self.avg_pool(x).flatten(1) | |
x = self.dropout(x) | |
x = self.fc(x) | |
return x | |
class DeepFakeClassifierGWAP(nn.Module): | |
def __init__(self, encoder, dropout_rate=0.5) -> None: | |
super().__init__() | |
self.encoder = encoder_params[encoder]["init_op"]() | |
self.avg_pool = GlobalWeightedAvgPool2d(encoder_params[encoder]["features"]) | |
self.dropout = Dropout(dropout_rate) | |
self.fc = Linear(encoder_params[encoder]["features"], 1) | |
def forward(self, x): | |
x = self.encoder.forward_features(x) | |
x = self.avg_pool(x).flatten(1) | |
x = self.dropout(x) | |
x = self.fc(x) | |
return x |