| |
| import torch |
| import torch.nn as nn |
| from mmcv.cnn import ConvModule |
| from mmengine.model import BaseModule |
| from mmengine.utils import digit_version, is_tuple_of |
| from torch import Tensor |
|
|
| from mmdet.utils import MultiConfig, OptConfigType, OptMultiConfig |
|
|
|
|
| class SELayer(BaseModule): |
| """Squeeze-and-Excitation Module. |
| |
| Args: |
| channels (int): The input (and output) channels of the SE layer. |
| ratio (int): Squeeze ratio in SELayer, the intermediate channel will be |
| ``int(channels/ratio)``. Defaults to 16. |
| conv_cfg (None or dict): Config dict for convolution layer. |
| Defaults to None, which means using conv2d. |
| act_cfg (dict or Sequence[dict]): Config dict for activation layer. |
| If act_cfg is a dict, two activation layers will be configurated |
| by this dict. If act_cfg is a sequence of dicts, the first |
| activation layer will be configurated by the first dict and the |
| second activation layer will be configurated by the second dict. |
| Defaults to (dict(type='ReLU'), dict(type='Sigmoid')) |
| init_cfg (dict or list[dict], optional): Initialization config dict. |
| Defaults to None |
| """ |
|
|
| def __init__(self, |
| channels: int, |
| ratio: int = 16, |
| conv_cfg: OptConfigType = None, |
| act_cfg: MultiConfig = (dict(type='ReLU'), |
| dict(type='Sigmoid')), |
| init_cfg: OptMultiConfig = None) -> None: |
| super().__init__(init_cfg=init_cfg) |
| if isinstance(act_cfg, dict): |
| act_cfg = (act_cfg, act_cfg) |
| assert len(act_cfg) == 2 |
| assert is_tuple_of(act_cfg, dict) |
| self.global_avgpool = nn.AdaptiveAvgPool2d(1) |
| self.conv1 = ConvModule( |
| in_channels=channels, |
| out_channels=int(channels / ratio), |
| kernel_size=1, |
| stride=1, |
| conv_cfg=conv_cfg, |
| act_cfg=act_cfg[0]) |
| self.conv2 = ConvModule( |
| in_channels=int(channels / ratio), |
| out_channels=channels, |
| kernel_size=1, |
| stride=1, |
| conv_cfg=conv_cfg, |
| act_cfg=act_cfg[1]) |
|
|
| def forward(self, x: Tensor) -> Tensor: |
| """Forward function for SELayer.""" |
| out = self.global_avgpool(x) |
| out = self.conv1(out) |
| out = self.conv2(out) |
| return x * out |
|
|
|
|
| class DyReLU(BaseModule): |
| """Dynamic ReLU (DyReLU) module. |
| |
| See `Dynamic ReLU <https://arxiv.org/abs/2003.10027>`_ for details. |
| Current implementation is specialized for task-aware attention in DyHead. |
| HSigmoid arguments in default act_cfg follow DyHead official code. |
| https://github.com/microsoft/DynamicHead/blob/master/dyhead/dyrelu.py |
| |
| Args: |
| channels (int): The input (and output) channels of DyReLU module. |
| ratio (int): Squeeze ratio in Squeeze-and-Excitation-like module, |
| the intermediate channel will be ``int(channels/ratio)``. |
| Defaults to 4. |
| conv_cfg (None or dict): Config dict for convolution layer. |
| Defaults to None, which means using conv2d. |
| act_cfg (dict or Sequence[dict]): Config dict for activation layer. |
| If act_cfg is a dict, two activation layers will be configurated |
| by this dict. If act_cfg is a sequence of dicts, the first |
| activation layer will be configurated by the first dict and the |
| second activation layer will be configurated by the second dict. |
| Defaults to (dict(type='ReLU'), dict(type='HSigmoid', bias=3.0, |
| divisor=6.0)) |
| init_cfg (dict or list[dict], optional): Initialization config dict. |
| Defaults to None |
| """ |
|
|
| def __init__(self, |
| channels: int, |
| ratio: int = 4, |
| conv_cfg: OptConfigType = None, |
| act_cfg: MultiConfig = (dict(type='ReLU'), |
| dict( |
| type='HSigmoid', |
| bias=3.0, |
| divisor=6.0)), |
| init_cfg: OptMultiConfig = None) -> None: |
| super().__init__(init_cfg=init_cfg) |
| if isinstance(act_cfg, dict): |
| act_cfg = (act_cfg, act_cfg) |
| assert len(act_cfg) == 2 |
| assert is_tuple_of(act_cfg, dict) |
| self.channels = channels |
| self.expansion = 4 |
| self.global_avgpool = nn.AdaptiveAvgPool2d(1) |
| self.conv1 = ConvModule( |
| in_channels=channels, |
| out_channels=int(channels / ratio), |
| kernel_size=1, |
| stride=1, |
| conv_cfg=conv_cfg, |
| act_cfg=act_cfg[0]) |
| self.conv2 = ConvModule( |
| in_channels=int(channels / ratio), |
| out_channels=channels * self.expansion, |
| kernel_size=1, |
| stride=1, |
| conv_cfg=conv_cfg, |
| act_cfg=act_cfg[1]) |
|
|
| def forward(self, x: Tensor) -> Tensor: |
| """Forward function.""" |
| coeffs = self.global_avgpool(x) |
| coeffs = self.conv1(coeffs) |
| coeffs = self.conv2(coeffs) - 0.5 |
| a1, b1, a2, b2 = torch.split(coeffs, self.channels, dim=1) |
| a1 = a1 * 2.0 + 1.0 |
| a2 = a2 * 2.0 |
| out = torch.max(x * a1 + b1, x * a2 + b2) |
| return out |
|
|
|
|
| class ChannelAttention(BaseModule): |
| """Channel attention Module. |
| |
| Args: |
| channels (int): The input (and output) channels of the attention layer. |
| init_cfg (dict or list[dict], optional): Initialization config dict. |
| Defaults to None |
| """ |
|
|
| def __init__(self, channels: int, init_cfg: OptMultiConfig = None) -> None: |
| super().__init__(init_cfg=init_cfg) |
| self.global_avgpool = nn.AdaptiveAvgPool2d(1) |
| self.fc = nn.Conv2d(channels, channels, 1, 1, 0, bias=True) |
| if digit_version(torch.__version__) < (1, 7, 0): |
| self.act = nn.Hardsigmoid() |
| else: |
| self.act = nn.Hardsigmoid(inplace=True) |
|
|
| def forward(self, x: Tensor) -> Tensor: |
| """Forward function for ChannelAttention.""" |
| with torch.cuda.amp.autocast(enabled=False): |
| out = self.global_avgpool(x) |
| out = self.fc(out) |
| out = self.act(out) |
| return x * out |
|
|
