File size: 5,543 Bytes
cd3346a
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
from functools import partial

import torch
from timm.models.efficientnet import tf_efficientnet_b3_ns, tf_efficientnet_b5_ns
from torch import nn
from torch.nn import Dropout2d, Conv2d
from torch.nn.modules.dropout import Dropout
from torch.nn.modules.linear import Linear
from torch.nn.modules.pooling import AdaptiveAvgPool2d
from torch.nn.modules.upsampling import UpsamplingBilinear2d

encoder_params = {
    "tf_efficientnet_b3_ns": {
        "features": 1536,
        "filters": [40, 32, 48, 136, 1536],
        "decoder_filters": [64, 128, 256, 256],
        "init_op": partial(tf_efficientnet_b3_ns, pretrained=True, drop_path_rate=0.2)
    },
    "tf_efficientnet_b5_ns": {
        "features": 2048,
        "filters": [48, 40, 64, 176, 2048],
        "decoder_filters": [64, 128, 256, 256],
        "init_op": partial(tf_efficientnet_b5_ns, pretrained=True, drop_path_rate=0.2)
    },
}


class DecoderBlock(nn.Module):
    def __init__(self, in_channels, out_channels):
        super().__init__()
        self.layer = nn.Sequential(
            nn.Upsample(scale_factor=2),
            nn.Conv2d(in_channels, out_channels, 3, padding=1),
            nn.ReLU(inplace=True)
        )

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


class ConcatBottleneck(nn.Module):
    def __init__(self, in_channels, out_channels):
        super().__init__()
        self.seq = nn.Sequential(
            nn.Conv2d(in_channels, out_channels, 3, padding=1),
            nn.ReLU(inplace=True)
        )

    def forward(self, dec, enc):
        x = torch.cat([dec, enc], dim=1)
        return self.seq(x)


class Decoder(nn.Module):
    def __init__(self, decoder_filters, filters, upsample_filters=None,
                 decoder_block=DecoderBlock, bottleneck=ConcatBottleneck, dropout=0):
        super().__init__()
        self.decoder_filters = decoder_filters
        self.filters = filters
        self.decoder_block = decoder_block
        self.decoder_stages = nn.ModuleList([self._get_decoder(idx) for idx in range(0, len(decoder_filters))])
        self.bottlenecks = nn.ModuleList([bottleneck(self.filters[-i - 2] + f, f)
                                          for i, f in enumerate(reversed(decoder_filters))])
        self.dropout = Dropout2d(dropout) if dropout > 0 else None
        self.last_block = None
        if upsample_filters:
            self.last_block = decoder_block(decoder_filters[0], out_channels=upsample_filters)
        else:
            self.last_block = UpsamplingBilinear2d(scale_factor=2)

    def forward(self, encoder_results: list):
        x = encoder_results[0]
        bottlenecks = self.bottlenecks
        for idx, bottleneck in enumerate(bottlenecks):
            rev_idx = - (idx + 1)
            x = self.decoder_stages[rev_idx](x)
            x = bottleneck(x, encoder_results[-rev_idx])
        if self.last_block:
            x = self.last_block(x)
        if self.dropout:
            x = self.dropout(x)
        return x

    def _get_decoder(self, layer):
        idx = layer + 1
        if idx == len(self.decoder_filters):
            in_channels = self.filters[idx]
        else:
            in_channels = self.decoder_filters[idx]
        return self.decoder_block(in_channels, self.decoder_filters[max(layer, 0)])


def _initialize_weights(module):
    for m in module.modules():
        if isinstance(m, nn.Conv2d) or isinstance(m, nn.ConvTranspose2d) or isinstance(m, nn.Linear):
            m.weight.data = nn.init.kaiming_normal_(m.weight.data)
            if m.bias is not None:
                m.bias.data.zero_()
        elif isinstance(m, nn.BatchNorm2d):
            m.weight.data.fill_(1)
            m.bias.data.zero_()


class EfficientUnetClassifier(nn.Module):
    def __init__(self, encoder, dropout_rate=0.5) -> None:
        super().__init__()
        self.decoder = Decoder(decoder_filters=encoder_params[encoder]["decoder_filters"],
                               filters=encoder_params[encoder]["filters"])
        self.avg_pool = AdaptiveAvgPool2d((1, 1))
        self.dropout = Dropout(dropout_rate)
        self.fc = Linear(encoder_params[encoder]["features"], 1)
        self.final = Conv2d(encoder_params[encoder]["decoder_filters"][0], out_channels=1, kernel_size=1, bias=False)
        _initialize_weights(self)
        self.encoder = encoder_params[encoder]["init_op"]()

    def get_encoder_features(self, x):
        encoder_results = []
        x = self.encoder.conv_stem(x)
        x = self.encoder.bn1(x)
        x = self.encoder.act1(x)
        encoder_results.append(x)
        x = self.encoder.blocks[:2](x)
        encoder_results.append(x)
        x = self.encoder.blocks[2:3](x)
        encoder_results.append(x)
        x = self.encoder.blocks[3:5](x)
        encoder_results.append(x)
        x = self.encoder.blocks[5:](x)
        x = self.encoder.conv_head(x)
        x = self.encoder.bn2(x)
        x = self.encoder.act2(x)
        encoder_results.append(x)
        encoder_results = list(reversed(encoder_results))
        return encoder_results

    def forward(self, x):
        encoder_results = self.get_encoder_features(x)
        seg = self.final(self.decoder(encoder_results))
        x = encoder_results[0]
        x = self.avg_pool(x).flatten(1)
        x = self.dropout(x)
        x = self.fc(x)
        return x, seg


if __name__ == '__main__':
    model = EfficientUnetClassifier("tf_efficientnet_b5_ns")
    model.eval()
    with torch.no_grad():
        input = torch.rand(4, 3, 224, 224)
        print(model(input))