File size: 4,895 Bytes
2e34814
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
'''
Adapted from https://github.com/cavalleria/cavaface.pytorch/blob/master/backbone/mobilefacenet.py
Original author cavalleria
'''

import torch.nn as nn
from torch.nn import Linear, Conv2d, BatchNorm1d, BatchNorm2d, PReLU, Sequential, Module
import torch


class Flatten(Module):
    def forward(self, x):
        return x.view(x.size(0), -1)


class ConvBlock(Module):
    def __init__(self, in_c, out_c, kernel=(1, 1), stride=(1, 1), padding=(0, 0), groups=1):
        super(ConvBlock, self).__init__()
        self.layers = nn.Sequential(
            Conv2d(in_c, out_c, kernel, groups=groups, stride=stride, padding=padding, bias=False),
            BatchNorm2d(num_features=out_c),
            PReLU(num_parameters=out_c)
        )

    def forward(self, x):
        return self.layers(x)


class LinearBlock(Module):
    def __init__(self, in_c, out_c, kernel=(1, 1), stride=(1, 1), padding=(0, 0), groups=1):
        super(LinearBlock, self).__init__()
        self.layers = nn.Sequential(
            Conv2d(in_c, out_c, kernel, stride, padding, groups=groups, bias=False),
            BatchNorm2d(num_features=out_c)
        )

    def forward(self, x):
        return self.layers(x)


class DepthWise(Module):
    def __init__(self, in_c, out_c, residual=False, kernel=(3, 3), stride=(2, 2), padding=(1, 1), groups=1):
        super(DepthWise, self).__init__()
        self.residual = residual
        self.layers = nn.Sequential(
            ConvBlock(in_c, out_c=groups, kernel=(1, 1), padding=(0, 0), stride=(1, 1)),
            ConvBlock(groups, groups, groups=groups, kernel=kernel, padding=padding, stride=stride),
            LinearBlock(groups, out_c, kernel=(1, 1), padding=(0, 0), stride=(1, 1))
        )

    def forward(self, x):
        short_cut = None
        if self.residual:
            short_cut = x
        x = self.layers(x)
        if self.residual:
            output = short_cut + x
        else:
            output = x
        return output


class Residual(Module):
    def __init__(self, c, num_block, groups, kernel=(3, 3), stride=(1, 1), padding=(1, 1)):
        super(Residual, self).__init__()
        modules = []
        for _ in range(num_block):
            modules.append(DepthWise(c, c, True, kernel, stride, padding, groups))
        self.layers = Sequential(*modules)

    def forward(self, x):
        return self.layers(x)


class GDC(Module):
    def __init__(self, embedding_size):
        super(GDC, self).__init__()
        self.layers = nn.Sequential(
            LinearBlock(512, 512, groups=512, kernel=(7, 7), stride=(1, 1), padding=(0, 0)),
            Flatten(),
            Linear(512, embedding_size, bias=False),
            BatchNorm1d(embedding_size))

    def forward(self, x):
        return self.layers(x)


class MobileFaceNet(Module):
    def __init__(self, fp16=False, num_features=512):
        super(MobileFaceNet, self).__init__()
        scale = 2
        self.fp16 = fp16
        self.layers = nn.Sequential(
            ConvBlock(3, 64 * scale, kernel=(3, 3), stride=(2, 2), padding=(1, 1)),
            ConvBlock(64 * scale, 64 * scale, kernel=(3, 3), stride=(1, 1), padding=(1, 1), groups=64),
            DepthWise(64 * scale, 64 * scale, kernel=(3, 3), stride=(2, 2), padding=(1, 1), groups=128),
            Residual(64 * scale, num_block=4, groups=128, kernel=(3, 3), stride=(1, 1), padding=(1, 1)),
            DepthWise(64 * scale, 128 * scale, kernel=(3, 3), stride=(2, 2), padding=(1, 1), groups=256),
            Residual(128 * scale, num_block=6, groups=256, kernel=(3, 3), stride=(1, 1), padding=(1, 1)),
            DepthWise(128 * scale, 128 * scale, kernel=(3, 3), stride=(2, 2), padding=(1, 1), groups=512),
            Residual(128 * scale, num_block=2, groups=256, kernel=(3, 3), stride=(1, 1), padding=(1, 1)),
        )
        self.conv_sep = ConvBlock(128 * scale, 512, kernel=(1, 1), stride=(1, 1), padding=(0, 0))
        self.features = GDC(num_features)
        self._initialize_weights()

    def _initialize_weights(self):
        for m in self.modules():
            if isinstance(m, nn.Conv2d):
                nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
                if m.bias is not None:
                    m.bias.data.zero_()
            elif isinstance(m, nn.BatchNorm2d):
                m.weight.data.fill_(1)
                m.bias.data.zero_()
            elif isinstance(m, nn.Linear):
                nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
                if m.bias is not None:
                    m.bias.data.zero_()

    def forward(self, x):
        with torch.cuda.amp.autocast(self.fp16):
            x = self.layers(x)
        x = self.conv_sep(x.float() if self.fp16 else x)
        x = self.features(x)
        return x


def get_mbf(fp16, num_features):
    return MobileFaceNet(fp16, num_features)