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| """ | |
| Copied from RT-DETR (https://github.com/lyuwenyu/RT-DETR) | |
| Copyright(c) 2023 lyuwenyu. All Rights Reserved. | |
| """ | |
| import torch | |
| import torch.nn as nn | |
| import torch.nn.functional as F | |
| from collections import OrderedDict | |
| from .common import get_activation, FrozenBatchNorm2d | |
| from ..core import register | |
| import os | |
| __all__ = ['PResNet'] | |
| ResNet_cfg = { | |
| 18: [2, 2, 2, 2], | |
| 34: [3, 4, 6, 3], | |
| 50: [3, 4, 6, 3], | |
| 101: [3, 4, 23, 3], | |
| # 152: [3, 8, 36, 3], | |
| } | |
| donwload_url = { | |
| 18: 'https://github.com/lyuwenyu/storage/releases/download/v0.1/ResNet18_vd_pretrained_from_paddle.pth', | |
| 34: 'https://github.com/lyuwenyu/storage/releases/download/v0.1/ResNet34_vd_pretrained_from_paddle.pth', | |
| 50: 'https://github.com/lyuwenyu/storage/releases/download/v0.1/ResNet50_vd_ssld_v2_pretrained_from_paddle.pth', | |
| 101: 'https://github.com/lyuwenyu/storage/releases/download/v0.1/ResNet101_vd_ssld_pretrained_from_paddle.pth', | |
| } | |
| local_weights = { | |
| 18: "ResNet18_vd_pretrained_from_paddle.pth", | |
| 34: "ResNet34_vd_pretrained_from_paddle.pth", | |
| 50: "ResNet50_vd_ssld_v2_pretrained_from_paddle.pth", | |
| 101: "ResNet101_vd_ssld_pretrained_from_paddle.pth" | |
| } | |
| class ConvNormLayer(nn.Module): | |
| def __init__(self, ch_in, ch_out, kernel_size, stride, padding=None, bias=False, act=None): | |
| super().__init__() | |
| self.conv = nn.Conv2d( | |
| ch_in, | |
| ch_out, | |
| kernel_size, | |
| stride, | |
| padding=(kernel_size-1)//2 if padding is None else padding, | |
| bias=bias) | |
| self.norm = nn.BatchNorm2d(ch_out) | |
| self.act = get_activation(act) | |
| def forward(self, x): | |
| return self.act(self.norm(self.conv(x))) | |
| class BasicBlock(nn.Module): | |
| expansion = 1 | |
| def __init__(self, ch_in, ch_out, stride, shortcut, act='relu', variant='b'): | |
| super().__init__() | |
| self.shortcut = shortcut | |
| if not shortcut: | |
| if variant == 'd' and stride == 2: | |
| self.short = nn.Sequential(OrderedDict([ | |
| ('pool', nn.AvgPool2d(2, 2, 0, ceil_mode=True)), | |
| ('conv', ConvNormLayer(ch_in, ch_out, 1, 1)) | |
| ])) | |
| else: | |
| self.short = ConvNormLayer(ch_in, ch_out, 1, stride) | |
| self.branch2a = ConvNormLayer(ch_in, ch_out, 3, stride, act=act) | |
| self.branch2b = ConvNormLayer(ch_out, ch_out, 3, 1, act=None) | |
| self.act = nn.Identity() if act is None else get_activation(act) | |
| def forward(self, x): | |
| out = self.branch2a(x) | |
| out = self.branch2b(out) | |
| if self.shortcut: | |
| short = x | |
| else: | |
| short = self.short(x) | |
| out = out + short | |
| out = self.act(out) | |
| return out | |
| class BottleNeck(nn.Module): | |
| expansion = 4 | |
| def __init__(self, ch_in, ch_out, stride, shortcut, act='relu', variant='b'): | |
| super().__init__() | |
| if variant == 'a': | |
| stride1, stride2 = stride, 1 | |
| else: | |
| stride1, stride2 = 1, stride | |
| width = ch_out | |
| self.branch2a = ConvNormLayer(ch_in, width, 1, stride1, act=act) | |
| self.branch2b = ConvNormLayer(width, width, 3, stride2, act=act) | |
| self.branch2c = ConvNormLayer(width, ch_out * self.expansion, 1, 1) | |
| self.shortcut = shortcut | |
| if not shortcut: | |
| if variant == 'd' and stride == 2: | |
| self.short = nn.Sequential(OrderedDict([ | |
| ('pool', nn.AvgPool2d(2, 2, 0, ceil_mode=True)), | |
| ('conv', ConvNormLayer(ch_in, ch_out * self.expansion, 1, 1)) | |
| ])) | |
| else: | |
| self.short = ConvNormLayer(ch_in, ch_out * self.expansion, 1, stride) | |
| self.act = nn.Identity() if act is None else get_activation(act) | |
| def forward(self, x): | |
| out = self.branch2a(x) | |
| out = self.branch2b(out) | |
| out = self.branch2c(out) | |
| if self.shortcut: | |
| short = x | |
| else: | |
| short = self.short(x) | |
| out = out + short | |
| out = self.act(out) | |
| return out | |
| class Blocks(nn.Module): | |
| def __init__(self, block, ch_in, ch_out, count, stage_num, act='relu', variant='b'): | |
| super().__init__() | |
| self.blocks = nn.ModuleList() | |
| for i in range(count): | |
| self.blocks.append( | |
| block( | |
| ch_in, | |
| ch_out, | |
| stride=2 if i == 0 and stage_num != 2 else 1, | |
| shortcut=False if i == 0 else True, | |
| variant=variant, | |
| act=act) | |
| ) | |
| if i == 0: | |
| ch_in = ch_out * block.expansion | |
| def forward(self, x): | |
| out = x | |
| for block in self.blocks: | |
| out = block(out) | |
| return out | |
| class PResNet(nn.Module): | |
| def __init__( | |
| self, | |
| depth, | |
| variant='d', | |
| num_stages=4, | |
| return_idx=[0, 1, 2, 3], | |
| act='relu', | |
| freeze_at=-1, | |
| freeze_norm=True, | |
| pretrained=False, | |
| local_model_dir='weights/resnets', | |
| ): | |
| super().__init__() | |
| block_nums = ResNet_cfg[depth] | |
| ch_in = 64 | |
| if variant in ['c', 'd']: | |
| conv_def = [ | |
| [3, ch_in // 2, 3, 2, "conv1_1"], | |
| [ch_in // 2, ch_in // 2, 3, 1, "conv1_2"], | |
| [ch_in // 2, ch_in, 3, 1, "conv1_3"], | |
| ] | |
| else: | |
| conv_def = [[3, ch_in, 7, 2, "conv1_1"]] | |
| self.conv1 = nn.Sequential(OrderedDict([ | |
| (name, ConvNormLayer(cin, cout, k, s, act=act)) for cin, cout, k, s, name in conv_def | |
| ])) | |
| ch_out_list = [64, 128, 256, 512] | |
| block = BottleNeck if depth >= 50 else BasicBlock | |
| _out_channels = [block.expansion * v for v in ch_out_list] | |
| _out_strides = [4, 8, 16, 32] | |
| self.res_layers = nn.ModuleList() | |
| for i in range(num_stages): | |
| stage_num = i + 2 | |
| self.res_layers.append( | |
| Blocks(block, ch_in, ch_out_list[i], block_nums[i], stage_num, act=act, variant=variant) | |
| ) | |
| ch_in = _out_channels[i] | |
| self.return_idx = return_idx | |
| self.out_channels = [_out_channels[_i] for _i in return_idx] | |
| self.out_strides = [_out_strides[_i] for _i in return_idx] | |
| if freeze_at >= 0: | |
| self._freeze_parameters(self.conv1) | |
| for i in range(min(freeze_at, num_stages)): | |
| self._freeze_parameters(self.res_layers[i]) | |
| if freeze_norm: | |
| self._freeze_norm(self) | |
| if pretrained: | |
| model_path = local_model_dir + local_weights[depth] | |
| if os.path.exists(model_path): | |
| state = torch.load(model_path, map_location='cpu') | |
| print(f"Loaded PResNet{depth} from local file@{model_path}.") | |
| else: | |
| if isinstance(pretrained, bool) or 'http' in pretrained: | |
| state = torch.hub.load_state_dict_from_url(donwload_url[depth], map_location='cpu', model_dir=local_model_dir) | |
| else: | |
| state = torch.load(pretrained, map_location='cpu') | |
| self.load_state_dict(state) | |
| print(f'Load PResNet{depth} state_dict') | |
| def _freeze_parameters(self, m: nn.Module): | |
| for p in m.parameters(): | |
| p.requires_grad = False | |
| def _freeze_norm(self, m: nn.Module): | |
| if isinstance(m, nn.BatchNorm2d): | |
| m = FrozenBatchNorm2d(m.num_features) | |
| else: | |
| for name, child in m.named_children(): | |
| _child = self._freeze_norm(child) | |
| if _child is not child: | |
| setattr(m, name, _child) | |
| return m | |
| def forward(self, x): | |
| conv1 = self.conv1(x) | |
| x = F.max_pool2d(conv1, kernel_size=3, stride=2, padding=1) | |
| outs = [] | |
| for idx, stage in enumerate(self.res_layers): | |
| x = stage(x) | |
| if idx in self.return_idx: | |
| outs.append(x) | |
| return outs | |