File size: 11,813 Bytes
2cd560a
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
# ------------------------------------------------------------------------------
# Adapted from https://github.com/akanazawa/hmr
# Original licence: Copyright (c) 2018 akanazawa, under the MIT License.
# ------------------------------------------------------------------------------

from abc import abstractmethod

import torch
import torch.nn as nn
from mmcv.cnn import normal_init, xavier_init

from mmpose.models.utils.geometry import batch_rodrigues


class BaseDiscriminator(nn.Module):
    """Base linear module for SMPL parameter discriminator.

    Args:
        fc_layers (Tuple): Tuple of neuron count,
            such as (9, 32, 32, 1)
        use_dropout (Tuple): Tuple of bool define use dropout or not
            for each layer, such as (True, True, False)
        drop_prob (Tuple): Tuple of float defined the drop prob,
            such as (0.5, 0.5, 0)
        use_activation(Tuple): Tuple of bool define use active function
            or not, such as (True, True, False)
    """

    def __init__(self, fc_layers, use_dropout, drop_prob, use_activation):
        super().__init__()
        self.fc_layers = fc_layers
        self.use_dropout = use_dropout
        self.drop_prob = drop_prob
        self.use_activation = use_activation
        self._check()
        self.create_layers()

    def _check(self):
        """Check input to avoid ValueError."""
        if not isinstance(self.fc_layers, tuple):
            raise TypeError(f'fc_layers require tuple, '
                            f'get {type(self.fc_layers)}')

        if not isinstance(self.use_dropout, tuple):
            raise TypeError(f'use_dropout require tuple, '
                            f'get {type(self.use_dropout)}')

        if not isinstance(self.drop_prob, tuple):
            raise TypeError(f'drop_prob require tuple, '
                            f'get {type(self.drop_prob)}')

        if not isinstance(self.use_activation, tuple):
            raise TypeError(f'use_activation require tuple, '
                            f'get {type(self.use_activation)}')

        l_fc_layer = len(self.fc_layers)
        l_use_drop = len(self.use_dropout)
        l_drop_prob = len(self.drop_prob)
        l_use_activation = len(self.use_activation)

        pass_check = (
            l_fc_layer >= 2 and l_use_drop < l_fc_layer
            and l_drop_prob < l_fc_layer and l_use_activation < l_fc_layer
            and l_drop_prob == l_use_drop)

        if not pass_check:
            msg = 'Wrong BaseDiscriminator parameters!'
            raise ValueError(msg)

    def create_layers(self):
        """Create layers."""
        l_fc_layer = len(self.fc_layers)
        l_use_drop = len(self.use_dropout)
        l_use_activation = len(self.use_activation)

        self.fc_blocks = nn.Sequential()

        for i in range(l_fc_layer - 1):
            self.fc_blocks.add_module(
                name=f'regressor_fc_{i}',
                module=nn.Linear(
                    in_features=self.fc_layers[i],
                    out_features=self.fc_layers[i + 1]))

            if i < l_use_activation and self.use_activation[i]:
                self.fc_blocks.add_module(
                    name=f'regressor_af_{i}', module=nn.ReLU())

            if i < l_use_drop and self.use_dropout[i]:
                self.fc_blocks.add_module(
                    name=f'regressor_fc_dropout_{i}',
                    module=nn.Dropout(p=self.drop_prob[i]))

    @abstractmethod
    def forward(self, inputs):
        """Forward function."""
        msg = 'the base class [BaseDiscriminator] is not callable!'
        raise NotImplementedError(msg)

    def init_weights(self):
        """Initialize model weights."""
        for m in self.fc_blocks.named_modules():
            if isinstance(m, nn.Linear):
                xavier_init(m, gain=0.01)


class ShapeDiscriminator(BaseDiscriminator):
    """Discriminator for SMPL shape parameters, the inputs is (batch_size x 10)

    Args:
        fc_layers (Tuple): Tuple of neuron count, such as (10, 5, 1)
        use_dropout (Tuple): Tuple of bool define use dropout or
            not for each layer, such as (True, True, False)
        drop_prob (Tuple): Tuple of float defined the drop prob,
            such as (0.5, 0)
        use_activation(Tuple): Tuple of bool define use active
            function or not, such as (True, False)
    """

    def __init__(self, fc_layers, use_dropout, drop_prob, use_activation):
        if fc_layers[-1] != 1:
            msg = f'the neuron count of the last layer ' \
                  f'must be 1, but got {fc_layers[-1]}'
            raise ValueError(msg)

        super().__init__(fc_layers, use_dropout, drop_prob, use_activation)

    def forward(self, inputs):
        """Forward function."""
        return self.fc_blocks(inputs)


class PoseDiscriminator(nn.Module):
    """Discriminator for SMPL pose parameters of each joint. It is composed of
    discriminators for each joints. The inputs is (batch_size x joint_count x
    9)

    Args:
        channels (Tuple): Tuple of channel number,
            such as (9, 32, 32, 1)
        joint_count (int): Joint number, such as 23
    """

    def __init__(self, channels, joint_count):
        super().__init__()
        if channels[-1] != 1:
            msg = f'the neuron count of the last layer ' \
                  f'must be 1, but got {channels[-1]}'
            raise ValueError(msg)
        self.joint_count = joint_count

        self.conv_blocks = nn.Sequential()
        len_channels = len(channels)
        for idx in range(len_channels - 2):
            self.conv_blocks.add_module(
                name=f'conv_{idx}',
                module=nn.Conv2d(
                    in_channels=channels[idx],
                    out_channels=channels[idx + 1],
                    kernel_size=1,
                    stride=1))

        self.fc_layer = nn.ModuleList()
        for idx in range(joint_count):
            self.fc_layer.append(
                nn.Linear(
                    in_features=channels[len_channels - 2], out_features=1))

    def forward(self, inputs):
        """Forward function.

        The input is (batch_size x joint_count x 9).
        """
        # shape: batch_size x 9 x 1 x joint_count
        inputs = inputs.transpose(1, 2).unsqueeze(2).contiguous()
        # shape: batch_size x c x 1 x joint_count
        internal_outputs = self.conv_blocks(inputs)
        outputs = []
        for idx in range(self.joint_count):
            outputs.append(self.fc_layer[idx](internal_outputs[:, :, 0, idx]))

        return torch.cat(outputs, 1), internal_outputs

    def init_weights(self):
        """Initialize model weights."""
        for m in self.conv_blocks:
            if isinstance(m, nn.Conv2d):
                normal_init(m, std=0.001, bias=0)
        for m in self.fc_layer.named_modules():
            if isinstance(m, nn.Linear):
                xavier_init(m, gain=0.01)


class FullPoseDiscriminator(BaseDiscriminator):
    """Discriminator for SMPL pose parameters of all joints.

    Args:
        fc_layers (Tuple): Tuple of neuron count,
            such as (736, 1024, 1024, 1)
        use_dropout (Tuple): Tuple of bool define use dropout or not
            for each layer, such as (True, True, False)
        drop_prob (Tuple): Tuple of float defined the drop prob,
            such as (0.5, 0.5, 0)
        use_activation(Tuple): Tuple of bool define use active
            function or not, such as (True, True, False)
    """

    def __init__(self, fc_layers, use_dropout, drop_prob, use_activation):
        if fc_layers[-1] != 1:
            msg = f'the neuron count of the last layer must be 1,' \
                  f' but got {fc_layers[-1]}'
            raise ValueError(msg)

        super().__init__(fc_layers, use_dropout, drop_prob, use_activation)

    def forward(self, inputs):
        """Forward function."""
        return self.fc_blocks(inputs)


class SMPLDiscriminator(nn.Module):
    """Discriminator for SMPL pose and shape parameters. It is composed of a
    discriminator for SMPL shape parameters, a discriminator for SMPL pose
    parameters of all joints  and a discriminator for SMPL pose parameters of
    each joint.

    Args:
        beta_channel (tuple of int): Tuple of neuron count of the
            discriminator of shape parameters. Defaults to (10, 5, 1)
        per_joint_channel (tuple of int): Tuple of neuron count of the
            discriminator of each joint. Defaults to (9, 32, 32, 1)
        full_pose_channel (tuple of int): Tuple of neuron count of the
            discriminator of full pose. Defaults to (23*32, 1024, 1024, 1)
    """

    def __init__(self,
                 beta_channel=(10, 5, 1),
                 per_joint_channel=(9, 32, 32, 1),
                 full_pose_channel=(23 * 32, 1024, 1024, 1)):
        super().__init__()
        self.joint_count = 23
        # The count of SMPL shape parameter is 10.
        assert beta_channel[0] == 10
        # Use 3 x 3 rotation matrix as the pose parameters
        # of each joint, so the input channel is 9.
        assert per_joint_channel[0] == 9
        assert self.joint_count * per_joint_channel[-2] \
            == full_pose_channel[0]

        self.beta_channel = beta_channel
        self.per_joint_channel = per_joint_channel
        self.full_pose_channel = full_pose_channel
        self._create_sub_modules()

    def _create_sub_modules(self):
        """Create sub discriminators."""

        # create theta discriminator for each joint
        self.pose_discriminator = PoseDiscriminator(self.per_joint_channel,
                                                    self.joint_count)

        # create full pose discriminator for total joints
        fc_layers = self.full_pose_channel
        use_dropout = tuple([False] * (len(fc_layers) - 1))
        drop_prob = tuple([0.5] * (len(fc_layers) - 1))
        use_activation = tuple([True] * (len(fc_layers) - 2) + [False])

        self.full_pose_discriminator = FullPoseDiscriminator(
            fc_layers, use_dropout, drop_prob, use_activation)

        # create shape discriminator for betas
        fc_layers = self.beta_channel
        use_dropout = tuple([False] * (len(fc_layers) - 1))
        drop_prob = tuple([0.5] * (len(fc_layers) - 1))
        use_activation = tuple([True] * (len(fc_layers) - 2) + [False])
        self.shape_discriminator = ShapeDiscriminator(fc_layers, use_dropout,
                                                      drop_prob,
                                                      use_activation)

    def forward(self, thetas):
        """Forward function."""
        _, poses, shapes = thetas

        batch_size = poses.shape[0]
        shape_disc_value = self.shape_discriminator(shapes)

        # The first rotation matrix is global rotation
        # and is NOT used in discriminator.
        if poses.dim() == 2:
            rotate_matrixs = \
                batch_rodrigues(poses.contiguous().view(-1, 3)
                                ).view(batch_size, 24, 9)[:, 1:, :]
        else:
            rotate_matrixs = poses.contiguous().view(batch_size, 24,
                                                     9)[:, 1:, :].contiguous()
        pose_disc_value, pose_inter_disc_value \
            = self.pose_discriminator(rotate_matrixs)
        full_pose_disc_value = self.full_pose_discriminator(
            pose_inter_disc_value.contiguous().view(batch_size, -1))
        return torch.cat(
            (pose_disc_value, full_pose_disc_value, shape_disc_value), 1)

    def init_weights(self):
        """Initialize model weights."""
        self.full_pose_discriminator.init_weights()
        self.pose_discriminator.init_weights()
        self.shape_discriminator.init_weights()