File size: 5,148 Bytes
506b122
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
9e0be78
506b122
9e0be78
506b122
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
9e0be78
506b122
 
 
 
 
 
 
 
 
 
 
 
 
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
import torch
import torch.nn as nn
from torch.nn import functional as F
from nets.CSPdarknet_tiny import darknet_tiny


class BasicConv(nn.Module):
    def __init__(self, in_channels, out_channels, kernel_size, stride=1):
        super(BasicConv, self).__init__()

        self.conv = nn.Conv2d(in_channels, out_channels, kernel_size, stride, kernel_size//2, bias=False)
        self.bn = nn.BatchNorm2d(out_channels)
        self.activation = nn.LeakyReLU(0.1)

    def forward(self, x):
        x = self.conv(x)
        x = self.bn(x)
        x = self.activation(x)
        return x

class Upsample(nn.Module):
    def __init__(self, in_channels, out_channels):
        super(Upsample, self).__init__()

        self.upsample = nn.Sequential(
            BasicConv(in_channels, out_channels, 1),
            nn.Upsample(scale_factor=2, mode='nearest')
        )

    def forward(self, x,):
        x = self.upsample(x)
        return x

def yolo_head(filters_list, in_filters):
    m = nn.Sequential(
        BasicConv(in_filters, filters_list[0], 3),
        nn.Conv2d(filters_list[0], filters_list[1], 1),
    )
    return m

class ConvBNReLU(nn.Module):
    '''Module for the Conv-BN-ReLU tuple.'''

    def __init__(self, c_in, c_out, kernel_size, stride, padding, dilation,
                 use_relu=True):
        super(ConvBNReLU, self).__init__()
        self.conv = nn.Conv2d(
            c_in, c_out, kernel_size=kernel_size, stride=stride,
            padding=padding, dilation=dilation, bias=False)
        self.bn = nn.BatchNorm2d(c_out)
        if use_relu:
            self.relu = nn.ReLU(inplace=True)
        else:
            self.relu = None

    def forward(self, x):
        x = self.conv(x)
        x = self.bn(x)
        if self.relu is not None:
            x = self.relu(x)
        return x


class CARAFE(nn.Module):
    def __init__(self, c, c_mid=64, scale=2, k_up=5, k_enc=3):
        """ The unofficial implementation of the CARAFE module.

        The details are in "https://arxiv.org/abs/1905.02188".

        Args:
            c: The channel number of the input and the output.
            c_mid: The channel number after compression.
            scale: The expected upsample scale.
            k_up: The size of the reassembly kernel.
            k_enc: The kernel size of the encoder.

        Returns:
            X: The upsampled feature map.
        """
        super(CARAFE, self).__init__()
        self.scale = scale

        self.comp = ConvBNReLU(c, c_mid, kernel_size=1, stride=1,
                               padding=0, dilation=1)
        self.enc = ConvBNReLU(c_mid, (scale * k_up) ** 2, kernel_size=k_enc,
                              stride=1, padding=k_enc // 2, dilation=1,
                              use_relu=False)
        self.pix_shf = nn.PixelShuffle(scale)

        self.upsmp = nn.Upsample(scale_factor=scale, mode='nearest')
        self.unfold = nn.Unfold(kernel_size=k_up, dilation=scale,
                                padding=k_up // 2 * scale)

    def forward(self, X):
        b, c, h, w = X.size()
        h_, w_ = h * self.scale, w * self.scale

        W = self.comp(X)  # b * m * h * w
        W = self.enc(W)  # b * 100 * h * w
        W = self.pix_shf(W)  # b * 25 * h_ * w_
        W = F.softmax(W, dim=1)  # b * 25 * h_ * w_

        X = self.upsmp(X)  # b * c * h_ * w_
        X = self.unfold(X)  # b * 25c * h_ * w_
        X = X.view(b, c, -1, h_, w_)  # b * 25 * c * h_ * w_

        X = torch.einsum('bkhw,bckhw->bchw', [W, X])  # b * c * h_ * w_
        return X

#---------------------------------------------------#
#   yolo_body--MSFNet
#---------------------------------------------------#
class YoloBody(nn.Module):
    def __init__(self, anchors_mask, num_classes, phi=0, backbone ='tiny', pretrained=False):
        super(YoloBody, self).__init__()
        if backbone == 'tiny':
            self.backbone  = darknet_tiny(pretrained)
            self.conv_for_P5    = BasicConv(512,256,1)
            self.yolo_headP5    = yolo_head([512, len(anchors_mask[0]) * (5 + num_classes)],256)
            self.upsample_1       = Upsample(256,128)
            self.conv1 = BasicConv(256,128,1)
            self.upsample_2 = CARAFE(128)
            self.yolo_headP4    = yolo_head([256, len(anchors_mask[1]) * (5 + num_classes)],384)

    def forward(self, x):

        feat1, feat2 = self.backbone(x)
        # 13,13,512 -> 13,13,256
        P5 = self.conv_for_P5(feat2)
        # 13,13,256 -> 13,13,512 -> 13,13,255
        out0 = self.yolo_headP5(P5)

        P6 = self.conv_for_P5(feat2)
        P6_Upsample = self.upsample_1(P6)

        # 13,13,256 -> 13,13,128 -> 26,26,128  
        P5 = self.conv1(P5)
        P5_Upsample = self.upsample_2(P5)

        sum = P5_Upsample + P6_Upsample
        # 26,26,256 + 26,26,128 -> 26,26,384
        # if 1 <= self.phi and self.phi <= 4:
        #     P5_Upsample = self.upsample_att(P5_Upsample)
        # P4 = torch.cat([P5_Upsample, feat1],axis=1)
        P4 = torch.cat([sum, feat1],axis=1)
        # 26,26,384 -> 26,26,256 -> 26,26,255
        out1 = self.yolo_headP4(P4)
        
        return out0, out1