File size: 6,058 Bytes
2c8b554
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import torch
import torch.nn as nn
import torch.nn.functional as F


class DenseFeatureExtractionModule(nn.Module):
    def __init__(self, use_relu=True, use_cuda=True):
        super(DenseFeatureExtractionModule, self).__init__()

        self.model = nn.Sequential(
            nn.Conv2d(3, 64, 3, padding=1),
            nn.ReLU(inplace=True),
            nn.Conv2d(64, 64, 3, padding=1),
            nn.ReLU(inplace=True),
            nn.MaxPool2d(2, stride=2),
            nn.Conv2d(64, 128, 3, padding=1),
            nn.ReLU(inplace=True),
            nn.Conv2d(128, 128, 3, padding=1),
            nn.ReLU(inplace=True),
            nn.MaxPool2d(2, stride=2),
            nn.Conv2d(128, 256, 3, padding=1),
            nn.ReLU(inplace=True),
            nn.Conv2d(256, 256, 3, padding=1),
            nn.ReLU(inplace=True),
            nn.Conv2d(256, 256, 3, padding=1),
            nn.ReLU(inplace=True),
            nn.AvgPool2d(2, stride=1),
            nn.Conv2d(256, 512, 3, padding=2, dilation=2),
            nn.ReLU(inplace=True),
            nn.Conv2d(512, 512, 3, padding=2, dilation=2),
            nn.ReLU(inplace=True),
            nn.Conv2d(512, 512, 3, padding=2, dilation=2),
        )
        self.num_channels = 512

        self.use_relu = use_relu

        if use_cuda:
            self.model = self.model.cuda()

    def forward(self, batch):
        output = self.model(batch)
        if self.use_relu:
            output = F.relu(output)
        return output


class D2Net(nn.Module):
    def __init__(self, model_file=None, use_relu=True, use_cuda=False):
        super(D2Net, self).__init__()

        self.dense_feature_extraction = DenseFeatureExtractionModule(
            use_relu=use_relu, use_cuda=use_cuda
        )

        self.detection = HardDetectionModule()

        self.localization = HandcraftedLocalizationModule()

        if model_file is not None:
            if use_cuda:
                self.load_state_dict(torch.load(model_file)['model'])
            else:
                self.load_state_dict(torch.load(model_file, map_location='cpu')['model'])

    def forward(self, batch):
        _, _, h, w = batch.size()
        dense_features = self.dense_feature_extraction(batch)

        detections = self.detection(dense_features)

        displacements = self.localization(dense_features)

        return {
            'dense_features': dense_features,
            'detections': detections,
            'displacements': displacements
        }


class HardDetectionModule(nn.Module):
    def __init__(self, edge_threshold=5):
        super(HardDetectionModule, self).__init__()

        self.edge_threshold = edge_threshold

        self.dii_filter = torch.tensor(
            [[0, 1., 0], [0, -2., 0], [0, 1., 0]]
        ).view(1, 1, 3, 3)
        self.dij_filter = 0.25 * torch.tensor(
            [[1., 0, -1.], [0, 0., 0], [-1., 0, 1.]]
        ).view(1, 1, 3, 3)
        self.djj_filter = torch.tensor(
            [[0, 0, 0], [1., -2., 1.], [0, 0, 0]]
        ).view(1, 1, 3, 3)

    def forward(self, batch):
        b, c, h, w = batch.size()
        device = batch.device

        depth_wise_max = torch.max(batch, dim=1)[0]
        is_depth_wise_max = (batch == depth_wise_max)
        del depth_wise_max

        local_max = F.max_pool2d(batch, 3, stride=1, padding=1)
        is_local_max = (batch == local_max)
        del local_max

        dii = F.conv2d(
            batch.view(-1, 1, h, w), self.dii_filter.to(device), padding=1
        ).view(b, c, h, w)
        dij = F.conv2d(
            batch.view(-1, 1, h, w), self.dij_filter.to(device), padding=1
        ).view(b, c, h, w)
        djj = F.conv2d(
            batch.view(-1, 1, h, w), self.djj_filter.to(device), padding=1
        ).view(b, c, h, w)

        det = dii * djj - dij * dij
        tr = dii + djj
        del dii, dij, djj

        threshold = (self.edge_threshold + 1) ** 2 / self.edge_threshold
        is_not_edge = torch.min(tr * tr / det <= threshold, det > 0)

        detected = torch.min(
            is_depth_wise_max,
            torch.min(is_local_max, is_not_edge)
        )
        del is_depth_wise_max, is_local_max, is_not_edge

        return detected


class HandcraftedLocalizationModule(nn.Module):
    def __init__(self):
        super(HandcraftedLocalizationModule, self).__init__()

        self.di_filter = torch.tensor(
            [[0, -0.5, 0], [0, 0, 0], [0,  0.5, 0]]
        ).view(1, 1, 3, 3)
        self.dj_filter = torch.tensor(
            [[0, 0, 0], [-0.5, 0, 0.5], [0, 0, 0]]
        ).view(1, 1, 3, 3)

        self.dii_filter = torch.tensor(
            [[0, 1., 0], [0, -2., 0], [0, 1., 0]]
        ).view(1, 1, 3, 3)
        self.dij_filter = 0.25 * torch.tensor(
            [[1., 0, -1.], [0, 0., 0], [-1., 0, 1.]]
        ).view(1, 1, 3, 3)
        self.djj_filter = torch.tensor(
            [[0, 0, 0], [1., -2., 1.], [0, 0, 0]]
        ).view(1, 1, 3, 3)

    def forward(self, batch):
        b, c, h, w = batch.size()
        device = batch.device

        dii = F.conv2d(
            batch.view(-1, 1, h, w), self.dii_filter.to(device), padding=1
        ).view(b, c, h, w)
        dij = F.conv2d(
            batch.view(-1, 1, h, w), self.dij_filter.to(device), padding=1
        ).view(b, c, h, w)
        djj = F.conv2d(
            batch.view(-1, 1, h, w), self.djj_filter.to(device), padding=1
        ).view(b, c, h, w)
        det = dii * djj - dij * dij

        inv_hess_00 = djj / det
        inv_hess_01 = -dij / det
        inv_hess_11 = dii / det
        del dii, dij, djj, det

        di = F.conv2d(
            batch.view(-1, 1, h, w), self.di_filter.to(device), padding=1
        ).view(b, c, h, w)
        dj = F.conv2d(
            batch.view(-1, 1, h, w), self.dj_filter.to(device), padding=1
        ).view(b, c, h, w)

        step_i = -(inv_hess_00 * di + inv_hess_01 * dj)
        step_j = -(inv_hess_01 * di + inv_hess_11 * dj)
        del inv_hess_00, inv_hess_01, inv_hess_11, di, dj

        return torch.stack([step_i, step_j], dim=1)