File size: 6,733 Bytes
e1aaa1a
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
# MIT License

# Copyright (c) 2022 Intelligent Systems Lab Org

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# File author: Shariq Farooq Bhat

import torch
import torch.nn as nn


class SeedBinRegressor(nn.Module):
    def __init__(self, in_features, n_bins=16, mlp_dim=256, min_depth=1e-3, max_depth=10):
        """Bin center regressor network. Bin centers are bounded on (min_depth, max_depth) interval.

        Args:
            in_features (int): input channels
            n_bins (int, optional): Number of bin centers. Defaults to 16.
            mlp_dim (int, optional): Hidden dimension. Defaults to 256.
            min_depth (float, optional): Min depth value. Defaults to 1e-3.
            max_depth (float, optional): Max depth value. Defaults to 10.
        """
        super().__init__()
        self.version = "1_1"
        self.min_depth = min_depth
        self.max_depth = max_depth

        self._net = nn.Sequential(
            nn.Conv2d(in_features, mlp_dim, 1, 1, 0),
            nn.ReLU(inplace=True),
            nn.Conv2d(mlp_dim, n_bins, 1, 1, 0),
            nn.ReLU(inplace=True)
        )

    def forward(self, x):
        """
        Returns tensor of bin_width vectors (centers). One vector b for every pixel
        """
        B = self._net(x)
        eps = 1e-3
        B = B + eps
        B_widths_normed = B / B.sum(dim=1, keepdim=True)
        B_widths = (self.max_depth - self.min_depth) * \
            B_widths_normed  # .shape NCHW
        # pad has the form (left, right, top, bottom, front, back)
        B_widths = nn.functional.pad(
            B_widths, (0, 0, 0, 0, 1, 0), mode='constant', value=self.min_depth)
        B_edges = torch.cumsum(B_widths, dim=1)  # .shape NCHW

        B_centers = 0.5 * (B_edges[:, :-1, ...] + B_edges[:, 1:, ...])
        return B_widths_normed, B_centers


class SeedBinRegressorUnnormed(nn.Module):
    def __init__(self, in_features, n_bins=16, mlp_dim=256, min_depth=1e-3, max_depth=10):
        """Bin center regressor network. Bin centers are unbounded

        Args:
            in_features (int): input channels
            n_bins (int, optional): Number of bin centers. Defaults to 16.
            mlp_dim (int, optional): Hidden dimension. Defaults to 256.
            min_depth (float, optional): Not used. (for compatibility with SeedBinRegressor)
            max_depth (float, optional): Not used. (for compatibility with SeedBinRegressor)
        """
        super().__init__()
        self.version = "1_1"
        self._net = nn.Sequential(
            nn.Conv2d(in_features, mlp_dim, 1, 1, 0),
            nn.ReLU(inplace=True),
            nn.Conv2d(mlp_dim, n_bins, 1, 1, 0),
            nn.Softplus()
        )

    def forward(self, x):
        """
        Returns tensor of bin_width vectors (centers). One vector b for every pixel
        """
        B_centers = self._net(x)
        return B_centers, B_centers


class Projector(nn.Module):
    def __init__(self, in_features, out_features, mlp_dim=128):
        """Projector MLP

        Args:
            in_features (int): input channels
            out_features (int): output channels
            mlp_dim (int, optional): hidden dimension. Defaults to 128.
        """
        super().__init__()

        self._net = nn.Sequential(
            nn.Conv2d(in_features, mlp_dim, 1, 1, 0),
            nn.ReLU(inplace=True),
            nn.Conv2d(mlp_dim, out_features, 1, 1, 0),
        )

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



class LinearSplitter(nn.Module):
    def __init__(self, in_features, prev_nbins, split_factor=2, mlp_dim=128, min_depth=1e-3, max_depth=10):
        super().__init__()

        self.prev_nbins = prev_nbins
        self.split_factor = split_factor
        self.min_depth = min_depth
        self.max_depth = max_depth

        self._net = nn.Sequential(
            nn.Conv2d(in_features, mlp_dim, 1, 1, 0),
            nn.GELU(),
            nn.Conv2d(mlp_dim, prev_nbins * split_factor, 1, 1, 0),
            nn.ReLU()
        )
    
    def forward(self, x, b_prev, prev_b_embedding=None, interpolate=True, is_for_query=False):
        """
        x : feature block; shape - n, c, h, w
        b_prev : previous bin widths normed; shape - n, prev_nbins, h, w
        """
        if prev_b_embedding is not None:
            if interpolate:
                prev_b_embedding = nn.functional.interpolate(prev_b_embedding, x.shape[-2:], mode='bilinear', align_corners=True)
            x = x + prev_b_embedding
        S = self._net(x)
        eps = 1e-3
        S = S + eps
        n, c, h, w = S.shape
        S = S.view(n, self.prev_nbins, self.split_factor, h, w)
        S_normed = S / S.sum(dim=2, keepdim=True)  # fractional splits

        b_prev = nn.functional.interpolate(b_prev, (h,w), mode='bilinear', align_corners=True)
        

        b_prev = b_prev / b_prev.sum(dim=1, keepdim=True)  # renormalize for gurantees
        # print(b_prev.shape, S_normed.shape)
        # if is_for_query:(1).expand(-1, b_prev.size(0)//n, -1, -1, -1, -1).flatten(0,1)  # TODO ? can replace all this with a single torch.repeat?
        b = b_prev.unsqueeze(2) * S_normed
        b = b.flatten(1,2)  # .shape n, prev_nbins * split_factor, h, w

        # calculate bin centers for loss calculation
        B_widths = (self.max_depth - self.min_depth) * b  # .shape N, nprev * splitfactor, H, W
        # pad has the form (left, right, top, bottom, front, back)
        B_widths = nn.functional.pad(B_widths, (0,0,0,0,1,0), mode='constant', value=self.min_depth)
        B_edges = torch.cumsum(B_widths, dim=1)  # .shape NCHW

        B_centers = 0.5 * (B_edges[:, :-1, ...] + B_edges[:,1:,...])
        return b, B_centers