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Running on Zero
File size: 3,468 Bytes
04012a7 | 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 | from typing import List, Optional
import torch
import torch.nn as nn
import torch.nn.functional as F
class ImageEncoder(nn.Module):
def __init__(
self,
trunk: nn.Module,
neck: nn.Module,
scalp: int = 0,
):
super().__init__()
self.trunk = trunk
self.neck = neck
self.scalp = scalp
assert (
self.trunk.channel_list == self.neck.backbone_channel_list
), f"Channel dims of trunk and neck do not match. Trunk: {self.trunk.channel_list}, neck: {self.neck.backbone_channel_list}"
def forward(self, sample: torch.Tensor):
features, pos = self.neck(self.trunk(sample))
if self.scalp > 0:
features, pos = features[: -self.scalp], pos[: -self.scalp]
src = features[-1]
output = {
"vision_features": src,
"vision_pos_enc": pos,
"backbone_fpn": features,
}
return output
class FpnNeck(nn.Module):
def __init__(
self,
position_encoding: nn.Module,
d_model: int,
backbone_channel_list: List[int],
kernel_size: int = 1,
stride: int = 1,
padding: int = 0,
fpn_interp_model: str = "bilinear",
fuse_type: str = "sum",
fpn_top_down_levels: Optional[List[int]] = None,
):
super().__init__()
self.position_encoding = position_encoding
self.convs = nn.ModuleList()
self.backbone_channel_list = backbone_channel_list
self.d_model = d_model
for dim in backbone_channel_list:
current = nn.Sequential()
current.add_module(
"conv",
nn.Conv2d(
in_channels=dim,
out_channels=d_model,
kernel_size=kernel_size,
stride=stride,
padding=padding,
),
)
self.convs.append(current)
self.fpn_interp_model = fpn_interp_model
assert fuse_type in ["sum", "avg"]
self.fuse_type = fuse_type
if fpn_top_down_levels is None:
fpn_top_down_levels = range(len(self.convs))
self.fpn_top_down_levels = list(fpn_top_down_levels)
def forward(self, xs: List[torch.Tensor]):
out = [None] * len(self.convs)
pos = [None] * len(self.convs)
assert len(xs) == len(self.convs)
prev_features = None
n = len(self.convs) - 1
for i in range(n, -1, -1):
x = xs[i]
lateral_features = self.convs[n - i](x)
if i in self.fpn_top_down_levels and prev_features is not None:
top_down_features = F.interpolate(
prev_features.to(dtype=torch.float32),
scale_factor=2.0,
mode=self.fpn_interp_model,
align_corners=(
None if self.fpn_interp_model == "nearest" else False
),
antialias=False,
)
prev_features = lateral_features + top_down_features
if self.fuse_type == "avg":
prev_features /= 2
else:
prev_features = lateral_features
x_out = prev_features
out[i] = x_out
pos[i] = self.position_encoding(x_out).to(x_out.dtype)
return out, pos
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