| import torch.nn as nn |
| import math |
| import torch.utils.model_zoo as model_zoo |
| BatchNorm2d = nn.BatchNorm2d |
|
|
| __all__ = ['ResNet', 'resnet18', 'resnet34', 'resnet50', 'resnet101', |
| 'resnet152'] |
|
|
|
|
| model_urls = { |
| 'resnet18': 'https://download.pytorch.org/models/resnet18-5c106cde.pth', |
| 'resnet34': 'https://download.pytorch.org/models/resnet34-333f7ec4.pth', |
| 'resnet50': 'https://download.pytorch.org/models/resnet50-19c8e357.pth', |
| 'resnet101': 'https://download.pytorch.org/models/resnet101-5d3b4d8f.pth', |
| 'resnet152': 'https://download.pytorch.org/models/resnet152-b121ed2d.pth', |
| } |
|
|
|
|
| def constant_init(module, constant, bias=0): |
| nn.init.constant_(module.weight, constant) |
| if hasattr(module, 'bias'): |
| nn.init.constant_(module.bias, bias) |
|
|
|
|
| def conv3x3(in_planes, out_planes, stride=1): |
| """3x3 convolution with padding""" |
| return nn.Conv2d(in_planes, out_planes, kernel_size=3, stride=stride, |
| padding=1, bias=False) |
|
|
|
|
| class BasicBlock(nn.Module): |
| expansion = 1 |
|
|
| def __init__(self, inplanes, planes, stride=1, downsample=None, dcn=None): |
| super(BasicBlock, self).__init__() |
| self.with_dcn = dcn is not None |
| self.conv1 = conv3x3(inplanes, planes, stride) |
| self.bn1 = BatchNorm2d(planes) |
| self.relu = nn.ReLU(inplace=True) |
| self.with_modulated_dcn = False |
| if self.with_dcn: |
| fallback_on_stride = dcn.get('fallback_on_stride', False) |
| self.with_modulated_dcn = dcn.get('modulated', False) |
| |
| if not self.with_dcn or fallback_on_stride: |
| self.conv2 = nn.Conv2d(planes, planes, kernel_size=3, |
| padding=1, bias=False) |
| else: |
| deformable_groups = dcn.get('deformable_groups', 1) |
| if not self.with_modulated_dcn: |
| from assets.ops.dcn import DeformConv |
| conv_op = DeformConv |
| offset_channels = 18 |
| else: |
| from assets.ops.dcn import ModulatedDeformConv |
| conv_op = ModulatedDeformConv |
| offset_channels = 27 |
| self.conv2_offset = nn.Conv2d( |
| planes, |
| deformable_groups * offset_channels, |
| kernel_size=3, |
| padding=1) |
| self.conv2 = conv_op( |
| planes, |
| planes, |
| kernel_size=3, |
| padding=1, |
| deformable_groups=deformable_groups, |
| bias=False) |
| self.bn2 = BatchNorm2d(planes) |
| self.downsample = downsample |
| self.stride = stride |
|
|
| def forward(self, x): |
| residual = x |
|
|
| out = self.conv1(x) |
| out = self.bn1(out) |
| out = self.relu(out) |
|
|
| |
| if not self.with_dcn: |
| out = self.conv2(out) |
| elif self.with_modulated_dcn: |
| offset_mask = self.conv2_offset(out) |
| offset = offset_mask[:, :18, :, :] |
| mask = offset_mask[:, -9:, :, :].sigmoid() |
| out = self.conv2(out, offset, mask) |
| else: |
| offset = self.conv2_offset(out) |
| out = self.conv2(out, offset) |
| out = self.bn2(out) |
|
|
| if self.downsample is not None: |
| residual = self.downsample(x) |
|
|
| out += residual |
| out = self.relu(out) |
|
|
| return out |
|
|
|
|
| class Bottleneck(nn.Module): |
| expansion = 4 |
|
|
| def __init__(self, inplanes, planes, stride=1, downsample=None, dcn=None): |
| super(Bottleneck, self).__init__() |
| self.with_dcn = dcn is not None |
| self.conv1 = nn.Conv2d(inplanes, planes, kernel_size=1, bias=False) |
| self.bn1 = BatchNorm2d(planes) |
| fallback_on_stride = False |
| self.with_modulated_dcn = False |
| if self.with_dcn: |
| fallback_on_stride = dcn.get('fallback_on_stride', False) |
| self.with_modulated_dcn = dcn.get('modulated', False) |
| if not self.with_dcn or fallback_on_stride: |
| self.conv2 = nn.Conv2d(planes, planes, kernel_size=3, |
| stride=stride, padding=1, bias=False) |
| else: |
| deformable_groups = dcn.get('deformable_groups', 1) |
| if not self.with_modulated_dcn: |
| from assets.ops.dcn import DeformConv |
| conv_op = DeformConv |
| offset_channels = 18 |
| else: |
| from assets.ops.dcn import ModulatedDeformConv |
| conv_op = ModulatedDeformConv |
| offset_channels = 27 |
| self.conv2_offset = nn.Conv2d( |
| planes, deformable_groups * offset_channels, |
| kernel_size=3, |
| padding=1) |
| self.conv2 = conv_op( |
| planes, planes, kernel_size=3, padding=1, stride=stride, |
| deformable_groups=deformable_groups, bias=False) |
| self.bn2 = BatchNorm2d(planes) |
| self.conv3 = nn.Conv2d(planes, planes * 4, kernel_size=1, bias=False) |
| self.bn3 = BatchNorm2d(planes * 4) |
| self.relu = nn.ReLU(inplace=True) |
| self.downsample = downsample |
| self.stride = stride |
| self.dcn = dcn |
| self.with_dcn = dcn is not None |
|
|
| def forward(self, x): |
| residual = x |
|
|
| out = self.conv1(x) |
| out = self.bn1(out) |
| out = self.relu(out) |
|
|
| |
| if not self.with_dcn: |
| out = self.conv2(out) |
| elif self.with_modulated_dcn: |
| offset_mask = self.conv2_offset(out) |
| offset = offset_mask[:, :18, :, :] |
| mask = offset_mask[:, -9:, :, :].sigmoid() |
| out = self.conv2(out, offset, mask) |
| else: |
| offset = self.conv2_offset(out) |
| out = self.conv2(out, offset) |
| out = self.bn2(out) |
| out = self.relu(out) |
|
|
| out = self.conv3(out) |
| out = self.bn3(out) |
|
|
| if self.downsample is not None: |
| residual = self.downsample(x) |
|
|
| out += residual |
| out = self.relu(out) |
|
|
| return out |
|
|
|
|
| class ResNet(nn.Module): |
| def __init__(self, block, layers, num_classes=1000, |
| dcn=None, stage_with_dcn=(False, False, False, False)): |
| self.dcn = dcn |
| self.stage_with_dcn = stage_with_dcn |
| self.inplanes = 64 |
| super(ResNet, self).__init__() |
| self.conv1 = nn.Conv2d(3, 64, kernel_size=7, stride=2, padding=3, |
| bias=False) |
| self.bn1 = BatchNorm2d(64) |
| self.relu = nn.ReLU(inplace=True) |
| self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1) |
| self.layer1 = self._make_layer(block, 64, layers[0]) |
| self.layer2 = self._make_layer( |
| block, 128, layers[1], stride=2, dcn=dcn) |
| self.layer3 = self._make_layer( |
| block, 256, layers[2], stride=2, dcn=dcn) |
| self.layer4 = self._make_layer( |
| block, 512, layers[3], stride=2, dcn=dcn) |
| self.avgpool = nn.AvgPool2d(7, stride=1) |
| self.fc = nn.Linear(512 * block.expansion, num_classes) |
| |
| self.smooth = nn.Conv2d(2048, 256, kernel_size=1, stride=1, padding=1) |
|
|
| for m in self.modules(): |
| if isinstance(m, nn.Conv2d): |
| n = m.kernel_size[0] * m.kernel_size[1] * m.out_channels |
| m.weight.data.normal_(0, math.sqrt(2. / n)) |
| elif isinstance(m, BatchNorm2d): |
| m.weight.data.fill_(1) |
| m.bias.data.zero_() |
| if self.dcn is not None: |
| for m in self.modules(): |
| if isinstance(m, Bottleneck) or isinstance(m, BasicBlock): |
| if hasattr(m, 'conv2_offset'): |
| constant_init(m.conv2_offset, 0) |
|
|
| def _make_layer(self, block, planes, blocks, stride=1, dcn=None): |
| downsample = None |
| if stride != 1 or self.inplanes != planes * block.expansion: |
| downsample = nn.Sequential( |
| nn.Conv2d(self.inplanes, planes * block.expansion, |
| kernel_size=1, stride=stride, bias=False), |
| BatchNorm2d(planes * block.expansion), |
| ) |
|
|
| layers = [] |
| layers.append(block(self.inplanes, planes, |
| stride, downsample, dcn=dcn)) |
| self.inplanes = planes * block.expansion |
| for i in range(1, blocks): |
| layers.append(block(self.inplanes, planes, dcn=dcn)) |
|
|
| return nn.Sequential(*layers) |
|
|
| def forward(self, x): |
| x = self.conv1(x) |
| x = self.bn1(x) |
| x = self.relu(x) |
| x = self.maxpool(x) |
|
|
| x2 = self.layer1(x) |
| x3 = self.layer2(x2) |
| x4 = self.layer3(x3) |
| x5 = self.layer4(x4) |
|
|
| return x2, x3, x4, x5 |
|
|
|
|
| def resnet18(pretrained=True, **kwargs): |
| """Constructs a ResNet-18 model. |
| Args: |
| pretrained (bool): If True, returns a model pre-trained on ImageNet |
| """ |
| model = ResNet(BasicBlock, [2, 2, 2, 2], **kwargs) |
| if pretrained: |
| model.load_state_dict(model_zoo.load_url( |
| model_urls['resnet18']), strict=False) |
| return model |
|
|
| def deformable_resnet18(pretrained=True, **kwargs): |
| """Constructs a ResNet-18 model. |
| Args: |
| pretrained (bool): If True, returns a model pre-trained on ImageNet |
| """ |
| model = ResNet(BasicBlock, [2, 2, 2, 2], |
| dcn=dict(modulated=True, |
| deformable_groups=1, |
| fallback_on_stride=False), |
| stage_with_dcn=[False, True, True, True], **kwargs) |
| |
| |
| |
| return model |
|
|
|
|
| def resnet34(pretrained=True, **kwargs): |
| """Constructs a ResNet-34 model. |
| Args: |
| pretrained (bool): If True, returns a model pre-trained on ImageNet |
| """ |
| model = ResNet(BasicBlock, [3, 4, 6, 3], **kwargs) |
| if pretrained: |
| model.load_state_dict(model_zoo.load_url( |
| model_urls['resnet34']), strict=False) |
| return model |
|
|
|
|
| def resnet50(pretrained=True, **kwargs): |
| """Constructs a ResNet-50 model. |
| Args: |
| pretrained (bool): If True, returns a model pre-trained on ImageNet |
| """ |
| model = ResNet(Bottleneck, [3, 4, 6, 3], **kwargs) |
| if pretrained: |
| model.load_state_dict(model_zoo.load_url( |
| model_urls['resnet50']), strict=False) |
| return model |
|
|
|
|
| def deformable_resnet50(pretrained=True, **kwargs): |
| """Constructs a ResNet-50 model with deformable conv. |
| Args: |
| pretrained (bool): If True, returns a model pre-trained on ImageNet |
| """ |
| model = ResNet(Bottleneck, [3, 4, 6, 3], |
| dcn=dict(modulated=True, |
| deformable_groups=1, |
| fallback_on_stride=False), |
| stage_with_dcn=[False, True, True, True], |
| **kwargs) |
| if pretrained: |
| model.load_state_dict(model_zoo.load_url( |
| model_urls['resnet50']), strict=False) |
| return model |
|
|
|
|
| def resnet101(pretrained=True, **kwargs): |
| """Constructs a ResNet-101 model. |
| Args: |
| pretrained (bool): If True, returns a model pre-trained on ImageNet |
| """ |
| model = ResNet(Bottleneck, [3, 4, 23, 3], **kwargs) |
| if pretrained: |
| model.load_state_dict(model_zoo.load_url( |
| model_urls['resnet101']), strict=False) |
| return model |
|
|
|
|
| def resnet152(pretrained=True, **kwargs): |
| """Constructs a ResNet-152 model. |
| Args: |
| pretrained (bool): If True, returns a model pre-trained on ImageNet |
| """ |
| model = ResNet(Bottleneck, [3, 8, 36, 3], **kwargs) |
| if pretrained: |
| model.load_state_dict(model_zoo.load_url( |
| model_urls['resnet152']), strict=False) |
| return model |
|
|
