File size: 5,678 Bytes
7a59a55
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import torch
import torch.nn as nn

from feature_networks.vit import forward_vit
from feature_networks.pretrained_builder import _make_pretrained
from feature_networks.constants import NORMALIZED_INCEPTION, NORMALIZED_IMAGENET, NORMALIZED_CLIP, VITS
from pg_modules.blocks import FeatureFusionBlock

def get_backbone_normstats(backbone):
    if backbone in NORMALIZED_INCEPTION:
        return {
            'mean': [0.5, 0.5, 0.5],
            'std': [0.5, 0.5, 0.5],
        }

    elif backbone in NORMALIZED_IMAGENET:
        return {
            'mean': [0.485, 0.456, 0.406],
            'std': [0.229, 0.224, 0.225],
        }

    elif backbone in NORMALIZED_CLIP:
        return {
            'mean': [0.48145466, 0.4578275, 0.40821073],
            'std': [0.26862954, 0.26130258, 0.27577711],
        }

    else:
        raise NotImplementedError

def _make_scratch_ccm(scratch, in_channels, cout, expand=False):
    # shapes
    out_channels = [cout, cout*2, cout*4, cout*8] if expand else [cout]*4

    scratch.layer0_ccm = nn.Conv2d(in_channels[0], out_channels[0], kernel_size=1, stride=1, padding=0, bias=True)
    scratch.layer1_ccm = nn.Conv2d(in_channels[1], out_channels[1], kernel_size=1, stride=1, padding=0, bias=True)
    scratch.layer2_ccm = nn.Conv2d(in_channels[2], out_channels[2], kernel_size=1, stride=1, padding=0, bias=True)
    scratch.layer3_ccm = nn.Conv2d(in_channels[3], out_channels[3], kernel_size=1, stride=1, padding=0, bias=True)

    scratch.CHANNELS = out_channels

    return scratch

def _make_scratch_csm(scratch, in_channels, cout, expand):
    scratch.layer3_csm = FeatureFusionBlock(in_channels[3], nn.ReLU(False), expand=expand, lowest=True)
    scratch.layer2_csm = FeatureFusionBlock(in_channels[2], nn.ReLU(False), expand=expand)
    scratch.layer1_csm = FeatureFusionBlock(in_channels[1], nn.ReLU(False), expand=expand)
    scratch.layer0_csm = FeatureFusionBlock(in_channels[0], nn.ReLU(False))

    # last refinenet does not expand to save channels in higher dimensions
    scratch.CHANNELS = [cout, cout, cout*2, cout*4] if expand else [cout]*4

    return scratch

def _make_projector(im_res, backbone, cout, proj_type, expand=False):
    assert proj_type in [0, 1, 2], "Invalid projection type"

    ### Build pretrained feature network
    pretrained = _make_pretrained(backbone)

    # Following Projected GAN
    im_res = 256
    pretrained.RESOLUTIONS = [im_res//4, im_res//8, im_res//16, im_res//32]

    if proj_type == 0: return pretrained, None

    ### Build CCM
    scratch = nn.Module()
    scratch = _make_scratch_ccm(scratch, in_channels=pretrained.CHANNELS, cout=cout, expand=expand)

    pretrained.CHANNELS = scratch.CHANNELS

    if proj_type == 1: return pretrained, scratch

    ### build CSM
    scratch = _make_scratch_csm(scratch, in_channels=scratch.CHANNELS, cout=cout, expand=expand)

    # CSM upsamples x2 so the feature map resolution doubles
    pretrained.RESOLUTIONS = [res*2 for res in pretrained.RESOLUTIONS]
    pretrained.CHANNELS = scratch.CHANNELS

    return pretrained, scratch

class F_Identity(nn.Module):
    def forward(self, x):
        return x

class F_RandomProj(nn.Module):
    def __init__(
        self,
        backbone="tf_efficientnet_lite3",
        im_res=256,
        cout=64,
        expand=True,
        proj_type=2,  # 0 = no projection, 1 = cross channel mixing, 2 = cross scale mixing
        **kwargs,
    ):
        super().__init__()
        self.proj_type = proj_type
        self.backbone = backbone
        self.cout = cout
        self.expand = expand
        self.normstats = get_backbone_normstats(backbone)

        # build pretrained feature network and random decoder (scratch)
        self.pretrained, self.scratch = _make_projector(im_res=im_res, backbone=self.backbone, cout=self.cout,
                                                        proj_type=self.proj_type, expand=self.expand)
        self.CHANNELS = self.pretrained.CHANNELS
        self.RESOLUTIONS = self.pretrained.RESOLUTIONS

    def forward(self, x):
        # predict feature maps
        if self.backbone in VITS:
            out0, out1, out2, out3 = forward_vit(self.pretrained, x)
        else:
            out0 = self.pretrained.layer0(x)
            out1 = self.pretrained.layer1(out0)
            out2 = self.pretrained.layer2(out1)
            out3 = self.pretrained.layer3(out2)

        # start enumerating at the lowest layer (this is where we put the first discriminator)
        out = {
            '0': out0,
            '1': out1,
            '2': out2,
            '3': out3,
        }

        if self.proj_type == 0: return out

        out0_channel_mixed = self.scratch.layer0_ccm(out['0'])
        out1_channel_mixed = self.scratch.layer1_ccm(out['1'])
        out2_channel_mixed = self.scratch.layer2_ccm(out['2'])
        out3_channel_mixed = self.scratch.layer3_ccm(out['3'])

        out = {
            '0': out0_channel_mixed,
            '1': out1_channel_mixed,
            '2': out2_channel_mixed,
            '3': out3_channel_mixed,
        }

        if self.proj_type == 1: return out

        # from bottom to top
        out3_scale_mixed = self.scratch.layer3_csm(out3_channel_mixed)
        out2_scale_mixed = self.scratch.layer2_csm(out3_scale_mixed, out2_channel_mixed)
        out1_scale_mixed = self.scratch.layer1_csm(out2_scale_mixed, out1_channel_mixed)
        out0_scale_mixed = self.scratch.layer0_csm(out1_scale_mixed, out0_channel_mixed)

        out = {
            '0': out0_scale_mixed,
            '1': out1_scale_mixed,
            '2': out2_scale_mixed,
            '3': out3_scale_mixed,
        }

        return out