File size: 9,499 Bytes
0324143
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
import torch
from torch import nn as nn
from torch.nn import functional as F

from basicsr.archs.vgg_arch import VGGFeatureExtractor
from basicsr.utils.registry import LOSS_REGISTRY
from .loss_util import weighted_loss

_reduction_modes = ['none', 'mean', 'sum']


@weighted_loss
def l1_loss(pred, target):
    return F.l1_loss(pred, target, reduction='none')


@weighted_loss
def mse_loss(pred, target):
    return F.mse_loss(pred, target, reduction='none')


@weighted_loss
def charbonnier_loss(pred, target, eps=1e-12):
    return torch.sqrt((pred - target)**2 + eps)


@LOSS_REGISTRY.register()
class L1Loss(nn.Module):
    """L1 (mean absolute error, MAE) loss.



    Args:

        loss_weight (float): Loss weight for L1 loss. Default: 1.0.

        reduction (str): Specifies the reduction to apply to the output.

            Supported choices are 'none' | 'mean' | 'sum'. Default: 'mean'.

    """

    def __init__(self, loss_weight=1.0, reduction='mean'):
        super(L1Loss, self).__init__()
        if reduction not in ['none', 'mean', 'sum']:
            raise ValueError(f'Unsupported reduction mode: {reduction}. Supported ones are: {_reduction_modes}')

        self.loss_weight = loss_weight
        self.reduction = reduction

    def forward(self, pred, target, weight=None, **kwargs):
        """

        Args:

            pred (Tensor): of shape (N, C, H, W). Predicted tensor.

            target (Tensor): of shape (N, C, H, W). Ground truth tensor.

            weight (Tensor, optional): of shape (N, C, H, W). Element-wise weights. Default: None.

        """
        return self.loss_weight * l1_loss(pred, target, weight, reduction=self.reduction)


@LOSS_REGISTRY.register()
class MSELoss(nn.Module):
    """MSE (L2) loss.



    Args:

        loss_weight (float): Loss weight for MSE loss. Default: 1.0.

        reduction (str): Specifies the reduction to apply to the output.

            Supported choices are 'none' | 'mean' | 'sum'. Default: 'mean'.

    """

    def __init__(self, loss_weight=1.0, reduction='mean'):
        super(MSELoss, self).__init__()
        if reduction not in ['none', 'mean', 'sum']:
            raise ValueError(f'Unsupported reduction mode: {reduction}. Supported ones are: {_reduction_modes}')

        self.loss_weight = loss_weight
        self.reduction = reduction

    def forward(self, pred, target, weight=None, **kwargs):
        """

        Args:

            pred (Tensor): of shape (N, C, H, W). Predicted tensor.

            target (Tensor): of shape (N, C, H, W). Ground truth tensor.

            weight (Tensor, optional): of shape (N, C, H, W). Element-wise weights. Default: None.

        """
        return self.loss_weight * mse_loss(pred, target, weight, reduction=self.reduction)


@LOSS_REGISTRY.register()
class CharbonnierLoss(nn.Module):
    """Charbonnier loss (one variant of Robust L1Loss, a differentiable

    variant of L1Loss).



    Described in "Deep Laplacian Pyramid Networks for Fast and Accurate

        Super-Resolution".



    Args:

        loss_weight (float): Loss weight for L1 loss. Default: 1.0.

        reduction (str): Specifies the reduction to apply to the output.

            Supported choices are 'none' | 'mean' | 'sum'. Default: 'mean'.

        eps (float): A value used to control the curvature near zero. Default: 1e-12.

    """

    def __init__(self, loss_weight=1.0, reduction='mean', eps=1e-12):
        super(CharbonnierLoss, self).__init__()
        if reduction not in ['none', 'mean', 'sum']:
            raise ValueError(f'Unsupported reduction mode: {reduction}. Supported ones are: {_reduction_modes}')

        self.loss_weight = loss_weight
        self.reduction = reduction
        self.eps = eps

    def forward(self, pred, target, weight=None, **kwargs):
        """

        Args:

            pred (Tensor): of shape (N, C, H, W). Predicted tensor.

            target (Tensor): of shape (N, C, H, W). Ground truth tensor.

            weight (Tensor, optional): of shape (N, C, H, W). Element-wise weights. Default: None.

        """
        return self.loss_weight * charbonnier_loss(pred, target, weight, eps=self.eps, reduction=self.reduction)


@LOSS_REGISTRY.register()
class WeightedTVLoss(L1Loss):
    """Weighted TV loss.



    Args:

        loss_weight (float): Loss weight. Default: 1.0.

    """

    def __init__(self, loss_weight=1.0, reduction='mean'):
        if reduction not in ['mean', 'sum']:
            raise ValueError(f'Unsupported reduction mode: {reduction}. Supported ones are: mean | sum')
        super(WeightedTVLoss, self).__init__(loss_weight=loss_weight, reduction=reduction)

    def forward(self, pred, weight=None):
        if weight is None:
            y_weight = None
            x_weight = None
        else:
            y_weight = weight[:, :, :-1, :]
            x_weight = weight[:, :, :, :-1]

        y_diff = super().forward(pred[:, :, :-1, :], pred[:, :, 1:, :], weight=y_weight)
        x_diff = super().forward(pred[:, :, :, :-1], pred[:, :, :, 1:], weight=x_weight)

        loss = x_diff + y_diff

        return loss


@LOSS_REGISTRY.register()
class PerceptualLoss(nn.Module):
    """Perceptual loss with commonly used style loss.



    Args:

        layer_weights (dict): The weight for each layer of vgg feature.

            Here is an example: {'conv5_4': 1.}, which means the conv5_4

            feature layer (before relu5_4) will be extracted with weight

            1.0 in calculating losses.

        vgg_type (str): The type of vgg network used as feature extractor.

            Default: 'vgg19'.

        use_input_norm (bool):  If True, normalize the input image in vgg.

            Default: True.

        range_norm (bool): If True, norm images with range [-1, 1] to [0, 1].

            Default: False.

        perceptual_weight (float): If `perceptual_weight > 0`, the perceptual

            loss will be calculated and the loss will multiplied by the

            weight. Default: 1.0.

        style_weight (float): If `style_weight > 0`, the style loss will be

            calculated and the loss will multiplied by the weight.

            Default: 0.

        criterion (str): Criterion used for perceptual loss. Default: 'l1'.

    """

    def __init__(self,

                 layer_weights,

                 vgg_type='vgg19',

                 use_input_norm=True,

                 range_norm=False,

                 perceptual_weight=1.0,

                 style_weight=0.,

                 criterion='l1'):
        super(PerceptualLoss, self).__init__()
        self.perceptual_weight = perceptual_weight
        self.style_weight = style_weight
        self.layer_weights = layer_weights
        self.vgg = VGGFeatureExtractor(
            layer_name_list=list(layer_weights.keys()),
            vgg_type=vgg_type,
            use_input_norm=use_input_norm,
            range_norm=range_norm)

        self.criterion_type = criterion
        if self.criterion_type == 'l1':
            self.criterion = torch.nn.L1Loss()
        elif self.criterion_type == 'l2':
            self.criterion = torch.nn.MSELoss()
        elif self.criterion_type == 'fro':
            self.criterion = None
        else:
            raise NotImplementedError(f'{criterion} criterion has not been supported.')

    def forward(self, x, gt):
        """Forward function.



        Args:

            x (Tensor): Input tensor with shape (n, c, h, w).

            gt (Tensor): Ground-truth tensor with shape (n, c, h, w).



        Returns:

            Tensor: Forward results.

        """
        # extract vgg features
        x_features = self.vgg(x)
        gt_features = self.vgg(gt.detach())

        # calculate perceptual loss
        if self.perceptual_weight > 0:
            percep_loss = 0
            for k in x_features.keys():
                if self.criterion_type == 'fro':
                    percep_loss += torch.norm(x_features[k] - gt_features[k], p='fro') * self.layer_weights[k]
                else:
                    percep_loss += self.criterion(x_features[k], gt_features[k]) * self.layer_weights[k]
            percep_loss *= self.perceptual_weight
        else:
            percep_loss = None

        # calculate style loss
        if self.style_weight > 0:
            style_loss = 0
            for k in x_features.keys():
                if self.criterion_type == 'fro':
                    style_loss += torch.norm(
                        self._gram_mat(x_features[k]) - self._gram_mat(gt_features[k]), p='fro') * self.layer_weights[k]
                else:
                    style_loss += self.criterion(self._gram_mat(x_features[k]), self._gram_mat(
                        gt_features[k])) * self.layer_weights[k]
            style_loss *= self.style_weight
        else:
            style_loss = None

        return percep_loss, style_loss

    def _gram_mat(self, x):
        """Calculate Gram matrix.



        Args:

            x (torch.Tensor): Tensor with shape of (n, c, h, w).



        Returns:

            torch.Tensor: Gram matrix.

        """
        n, c, h, w = x.size()
        features = x.view(n, c, w * h)
        features_t = features.transpose(1, 2)
        gram = features.bmm(features_t) / (c * h * w)
        return gram