File size: 8,397 Bytes
8f72b1f
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
from .mlp import MLP
from .positional_encoding import PositionalEncodingsFixed

import torch
from torch import nn

from torchvision.ops import roi_align


class OPEModule(nn.Module):

    def __init__(
        self,
        num_iterative_steps: int,
        emb_dim: int,
        kernel_dim: int,
        num_objects: int,
        num_heads: int,
        reduction: int,
        layer_norm_eps: float,
        mlp_factor: int,
        norm_first: bool,
        activation: nn.Module,
        norm: bool,
        zero_shot: bool,
    ):

        super(OPEModule, self).__init__()

        self.num_iterative_steps = num_iterative_steps
        self.zero_shot = zero_shot
        self.kernel_dim = kernel_dim
        self.num_objects = num_objects
        self.emb_dim = emb_dim
        self.reduction = reduction

        if num_iterative_steps > 0:
            self.iterative_adaptation = IterativeAdaptationModule(
                num_layers=num_iterative_steps, emb_dim=emb_dim, num_heads=num_heads,
                dropout=0, layer_norm_eps=layer_norm_eps,
                mlp_factor=mlp_factor, norm_first=norm_first,
                activation=activation, norm=norm,
                zero_shot=zero_shot
            )

        if not self.zero_shot:
            self.shape_or_objectness = nn.Sequential(
                nn.Linear(2, 64),
                nn.ReLU(),
                nn.Linear(64, emb_dim),
                nn.ReLU(),
                nn.Linear(emb_dim, self.kernel_dim**2 * emb_dim)
            )
        else:
            self.shape_or_objectness = nn.Parameter(
                torch.empty((self.num_objects, self.kernel_dim**2, emb_dim))
            )
            nn.init.normal_(self.shape_or_objectness)

        self.pos_emb = PositionalEncodingsFixed(emb_dim)

    def forward(self, f_e, pos_emb, bboxes):
        bs, _, h, w = f_e.size()
        # extract the shape features or objectness
        if not self.zero_shot:
            box_hw = torch.zeros(bboxes.size(0), bboxes.size(1), 2).to(bboxes.device)
            box_hw[:, :, 0] = bboxes[:, :, 2] - bboxes[:, :, 0]
            box_hw[:, :, 1] = bboxes[:, :, 3] - bboxes[:, :, 1]
            shape_or_objectness = self.shape_or_objectness(box_hw).reshape(
                bs, -1, self.kernel_dim ** 2, self.emb_dim
            ).flatten(1, 2).transpose(0, 1)
        else:
            shape_or_objectness = self.shape_or_objectness.expand(
                bs, -1, -1, -1
            ).flatten(1, 2).transpose(0, 1)

        # if not zero shot add appearance
        if not self.zero_shot:
            # reshape bboxes into the format suitable for roi_align
            num_of_boxes = bboxes.size(1)
            bboxes = torch.cat([
                torch.arange(
                    bs, requires_grad=False
                ).to(bboxes.device).repeat_interleave(num_of_boxes).reshape(-1, 1),
                bboxes.flatten(0, 1),
            ], dim=1)
            appearance = roi_align(
                f_e,
                boxes=bboxes, output_size=self.kernel_dim,
                spatial_scale=1.0 / self.reduction, aligned=True
            ).permute(0, 2, 3, 1).reshape(
                bs, num_of_boxes * self.kernel_dim ** 2, -1
            ).transpose(0, 1)
        else:
            num_of_boxes = self.num_objects
            appearance = None

        query_pos_emb = self.pos_emb(
            bs, self.kernel_dim, self.kernel_dim, f_e.device
        ).flatten(2).permute(2, 0, 1).repeat(num_of_boxes, 1, 1)

        if self.num_iterative_steps > 0:
            memory = f_e.flatten(2).permute(2, 0, 1)
            all_prototypes = self.iterative_adaptation(
                shape_or_objectness, appearance, memory, pos_emb, query_pos_emb
            )
        else:
            if shape_or_objectness is not None and appearance is not None:
                all_prototypes = (shape_or_objectness + appearance).unsqueeze(0)
            else:
                all_prototypes = (
                    shape_or_objectness if shape_or_objectness is not None else appearance
                ).unsqueeze(0)

        return all_prototypes



class IterativeAdaptationModule(nn.Module):

    def __init__(
        self,
        num_layers: int,
        emb_dim: int,
        num_heads: int,
        dropout: float,
        layer_norm_eps: float,
        mlp_factor: int,
        norm_first: bool,
        activation: nn.Module,
        norm: bool,
        zero_shot: bool
    ):

        super(IterativeAdaptationModule, self).__init__()

        self.layers = nn.ModuleList([
            IterativeAdaptationLayer(
                emb_dim, num_heads, dropout, layer_norm_eps,
                mlp_factor, norm_first, activation, zero_shot
            ) for i in range(num_layers)
        ])

        self.norm = nn.LayerNorm(emb_dim, layer_norm_eps) if norm else nn.Identity()

    def forward(
        self, tgt, appearance, memory, pos_emb, query_pos_emb, tgt_mask=None, memory_mask=None,
        tgt_key_padding_mask=None, memory_key_padding_mask=None
    ):

        output = tgt
        outputs = list()
        for i, layer in enumerate(self.layers):
            output = layer(
                output, appearance, memory, pos_emb, query_pos_emb, tgt_mask, memory_mask,
                tgt_key_padding_mask, memory_key_padding_mask
            )
            outputs.append(self.norm(output))

        return torch.stack(outputs)


class IterativeAdaptationLayer(nn.Module):

    def __init__(
        self,
        emb_dim: int,
        num_heads: int,
        dropout: float,
        layer_norm_eps: float,
        mlp_factor: int,
        norm_first: bool,
        activation: nn.Module,
        zero_shot: bool
    ):
        super(IterativeAdaptationLayer, self).__init__()

        self.norm_first = norm_first
        self.zero_shot = zero_shot

        if not self.zero_shot:
            self.norm1 = nn.LayerNorm(emb_dim, layer_norm_eps)
        self.norm2 = nn.LayerNorm(emb_dim, layer_norm_eps)
        self.norm3 = nn.LayerNorm(emb_dim, layer_norm_eps)
        if not self.zero_shot:
            self.dropout1 = nn.Dropout(dropout)
        self.dropout2 = nn.Dropout(dropout)
        self.dropout3 = nn.Dropout(dropout)

        if not self.zero_shot:
            self.self_attn = nn.MultiheadAttention(emb_dim, num_heads, dropout)
        self.enc_dec_attn = nn.MultiheadAttention(emb_dim, num_heads, dropout)

        self.mlp = MLP(emb_dim, mlp_factor * emb_dim, dropout, activation)

    def with_emb(self, x, emb):
        return x if emb is None else x + emb

    def forward(
        self, tgt, appearance, memory, pos_emb, query_pos_emb, tgt_mask, memory_mask,
        tgt_key_padding_mask, memory_key_padding_mask
    ):
        if self.norm_first:
            if not self.zero_shot:
                tgt_norm = self.norm1(tgt)
                tgt = tgt + self.dropout1(self.self_attn(
                    query=self.with_emb(tgt_norm, query_pos_emb),
                    key=self.with_emb(appearance, query_pos_emb),
                    value=appearance,
                    attn_mask=tgt_mask,
                    key_padding_mask=tgt_key_padding_mask
                )[0])

            tgt_norm = self.norm2(tgt)
            tgt = tgt + self.dropout2(self.enc_dec_attn(
                query=self.with_emb(tgt_norm, query_pos_emb),
                key=memory+pos_emb,
                value=memory,
                attn_mask=memory_mask,
                key_padding_mask=memory_key_padding_mask
            )[0])
            tgt_norm = self.norm3(tgt)
            tgt = tgt + self.dropout3(self.mlp(tgt_norm))

        else:
            if not self.zero_shot:
                tgt = self.norm1(tgt + self.dropout1(self.self_attn(
                    query=self.with_emb(tgt, query_pos_emb),
                    key=self.with_emb(appearance),
                    value=appearance,
                    attn_mask=tgt_mask,
                    key_padding_mask=tgt_key_padding_mask
                )[0]))

            tgt = self.norm2(tgt + self.dropout2(self.enc_dec_attn(
                query=self.with_emb(tgt, query_pos_emb),
                key=memory+pos_emb,
                value=memory,
                attn_mask=memory_mask,
                key_padding_mask=memory_key_padding_mask
            )[0]))

            tgt = self.norm3(tgt + self.dropout3(self.mlp(tgt)))

        return tgt