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# Copyright (c) Facebook, Inc. and its affiliates. | |
import fvcore.nn.weight_init as weight_init | |
import torch.nn.functional as F | |
from annotator.oneformer.detectron2.layers import CNNBlockBase, Conv2d, get_norm | |
from annotator.oneformer.detectron2.modeling import BACKBONE_REGISTRY | |
from annotator.oneformer.detectron2.modeling.backbone.resnet import ( | |
BasicStem, | |
BottleneckBlock, | |
DeformBottleneckBlock, | |
ResNet, | |
) | |
class DeepLabStem(CNNBlockBase): | |
""" | |
The DeepLab ResNet stem (layers before the first residual block). | |
""" | |
def __init__(self, in_channels=3, out_channels=128, norm="BN"): | |
""" | |
Args: | |
norm (str or callable): norm after the first conv layer. | |
See :func:`layers.get_norm` for supported format. | |
""" | |
super().__init__(in_channels, out_channels, 4) | |
self.in_channels = in_channels | |
self.conv1 = Conv2d( | |
in_channels, | |
out_channels // 2, | |
kernel_size=3, | |
stride=2, | |
padding=1, | |
bias=False, | |
norm=get_norm(norm, out_channels // 2), | |
) | |
self.conv2 = Conv2d( | |
out_channels // 2, | |
out_channels // 2, | |
kernel_size=3, | |
stride=1, | |
padding=1, | |
bias=False, | |
norm=get_norm(norm, out_channels // 2), | |
) | |
self.conv3 = Conv2d( | |
out_channels // 2, | |
out_channels, | |
kernel_size=3, | |
stride=1, | |
padding=1, | |
bias=False, | |
norm=get_norm(norm, out_channels), | |
) | |
weight_init.c2_msra_fill(self.conv1) | |
weight_init.c2_msra_fill(self.conv2) | |
weight_init.c2_msra_fill(self.conv3) | |
def forward(self, x): | |
x = self.conv1(x) | |
x = F.relu_(x) | |
x = self.conv2(x) | |
x = F.relu_(x) | |
x = self.conv3(x) | |
x = F.relu_(x) | |
x = F.max_pool2d(x, kernel_size=3, stride=2, padding=1) | |
return x | |
def build_resnet_deeplab_backbone(cfg, input_shape): | |
""" | |
Create a ResNet instance from config. | |
Returns: | |
ResNet: a :class:`ResNet` instance. | |
""" | |
# need registration of new blocks/stems? | |
norm = cfg.MODEL.RESNETS.NORM | |
if cfg.MODEL.RESNETS.STEM_TYPE == "basic": | |
stem = BasicStem( | |
in_channels=input_shape.channels, | |
out_channels=cfg.MODEL.RESNETS.STEM_OUT_CHANNELS, | |
norm=norm, | |
) | |
elif cfg.MODEL.RESNETS.STEM_TYPE == "deeplab": | |
stem = DeepLabStem( | |
in_channels=input_shape.channels, | |
out_channels=cfg.MODEL.RESNETS.STEM_OUT_CHANNELS, | |
norm=norm, | |
) | |
else: | |
raise ValueError("Unknown stem type: {}".format(cfg.MODEL.RESNETS.STEM_TYPE)) | |
# fmt: off | |
freeze_at = cfg.MODEL.BACKBONE.FREEZE_AT | |
out_features = cfg.MODEL.RESNETS.OUT_FEATURES | |
depth = cfg.MODEL.RESNETS.DEPTH | |
num_groups = cfg.MODEL.RESNETS.NUM_GROUPS | |
width_per_group = cfg.MODEL.RESNETS.WIDTH_PER_GROUP | |
bottleneck_channels = num_groups * width_per_group | |
in_channels = cfg.MODEL.RESNETS.STEM_OUT_CHANNELS | |
out_channels = cfg.MODEL.RESNETS.RES2_OUT_CHANNELS | |
stride_in_1x1 = cfg.MODEL.RESNETS.STRIDE_IN_1X1 | |
res4_dilation = cfg.MODEL.RESNETS.RES4_DILATION | |
res5_dilation = cfg.MODEL.RESNETS.RES5_DILATION | |
deform_on_per_stage = cfg.MODEL.RESNETS.DEFORM_ON_PER_STAGE | |
deform_modulated = cfg.MODEL.RESNETS.DEFORM_MODULATED | |
deform_num_groups = cfg.MODEL.RESNETS.DEFORM_NUM_GROUPS | |
res5_multi_grid = cfg.MODEL.RESNETS.RES5_MULTI_GRID | |
# fmt: on | |
assert res4_dilation in {1, 2}, "res4_dilation cannot be {}.".format(res4_dilation) | |
assert res5_dilation in {1, 2, 4}, "res5_dilation cannot be {}.".format(res5_dilation) | |
if res4_dilation == 2: | |
# Always dilate res5 if res4 is dilated. | |
assert res5_dilation == 4 | |
num_blocks_per_stage = {50: [3, 4, 6, 3], 101: [3, 4, 23, 3], 152: [3, 8, 36, 3]}[depth] | |
stages = [] | |
# Avoid creating variables without gradients | |
# It consumes extra memory and may cause allreduce to fail | |
out_stage_idx = [{"res2": 2, "res3": 3, "res4": 4, "res5": 5}[f] for f in out_features] | |
max_stage_idx = max(out_stage_idx) | |
for idx, stage_idx in enumerate(range(2, max_stage_idx + 1)): | |
if stage_idx == 4: | |
dilation = res4_dilation | |
elif stage_idx == 5: | |
dilation = res5_dilation | |
else: | |
dilation = 1 | |
first_stride = 1 if idx == 0 or dilation > 1 else 2 | |
stage_kargs = { | |
"num_blocks": num_blocks_per_stage[idx], | |
"stride_per_block": [first_stride] + [1] * (num_blocks_per_stage[idx] - 1), | |
"in_channels": in_channels, | |
"out_channels": out_channels, | |
"norm": norm, | |
} | |
stage_kargs["bottleneck_channels"] = bottleneck_channels | |
stage_kargs["stride_in_1x1"] = stride_in_1x1 | |
stage_kargs["dilation"] = dilation | |
stage_kargs["num_groups"] = num_groups | |
if deform_on_per_stage[idx]: | |
stage_kargs["block_class"] = DeformBottleneckBlock | |
stage_kargs["deform_modulated"] = deform_modulated | |
stage_kargs["deform_num_groups"] = deform_num_groups | |
else: | |
stage_kargs["block_class"] = BottleneckBlock | |
if stage_idx == 5: | |
stage_kargs.pop("dilation") | |
stage_kargs["dilation_per_block"] = [dilation * mg for mg in res5_multi_grid] | |
blocks = ResNet.make_stage(**stage_kargs) | |
in_channels = out_channels | |
out_channels *= 2 | |
bottleneck_channels *= 2 | |
stages.append(blocks) | |
return ResNet(stem, stages, out_features=out_features).freeze(freeze_at) | |