TTP / mmseg /models /necks /ic_neck.py
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# Copyright (c) OpenMMLab. All rights reserved.
import torch.nn.functional as F
from mmcv.cnn import ConvModule
from mmengine.model import BaseModule
from mmseg.registry import MODELS
from ..utils import resize
class CascadeFeatureFusion(BaseModule):
"""Cascade Feature Fusion Unit in ICNet.
Args:
low_channels (int): The number of input channels for
low resolution feature map.
high_channels (int): The number of input channels for
high resolution feature map.
out_channels (int): The number of output channels.
conv_cfg (dict): Dictionary to construct and config conv layer.
Default: None.
norm_cfg (dict): Dictionary to construct and config norm layer.
Default: dict(type='BN').
act_cfg (dict): Dictionary to construct and config act layer.
Default: dict(type='ReLU').
align_corners (bool): align_corners argument of F.interpolate.
Default: False.
init_cfg (dict or list[dict], optional): Initialization config dict.
Default: None.
Returns:
x (Tensor): The output tensor of shape (N, out_channels, H, W).
x_low (Tensor): The output tensor of shape (N, out_channels, H, W)
for Cascade Label Guidance in auxiliary heads.
"""
def __init__(self,
low_channels,
high_channels,
out_channels,
conv_cfg=None,
norm_cfg=dict(type='BN'),
act_cfg=dict(type='ReLU'),
align_corners=False,
init_cfg=None):
super().__init__(init_cfg=init_cfg)
self.align_corners = align_corners
self.conv_low = ConvModule(
low_channels,
out_channels,
3,
padding=2,
dilation=2,
conv_cfg=conv_cfg,
norm_cfg=norm_cfg,
act_cfg=act_cfg)
self.conv_high = ConvModule(
high_channels,
out_channels,
1,
conv_cfg=conv_cfg,
norm_cfg=norm_cfg,
act_cfg=act_cfg)
def forward(self, x_low, x_high):
x_low = resize(
x_low,
size=x_high.size()[2:],
mode='bilinear',
align_corners=self.align_corners)
# Note: Different from original paper, `x_low` is underwent
# `self.conv_low` rather than another 1x1 conv classifier
# before being used for auxiliary head.
x_low = self.conv_low(x_low)
x_high = self.conv_high(x_high)
x = x_low + x_high
x = F.relu(x, inplace=True)
return x, x_low
@MODELS.register_module()
class ICNeck(BaseModule):
"""ICNet for Real-Time Semantic Segmentation on High-Resolution Images.
This head is the implementation of `ICHead
<https://arxiv.org/abs/1704.08545>`_.
Args:
in_channels (int): The number of input image channels. Default: 3.
out_channels (int): The numbers of output feature channels.
Default: 128.
conv_cfg (dict): Dictionary to construct and config conv layer.
Default: None.
norm_cfg (dict): Dictionary to construct and config norm layer.
Default: dict(type='BN').
act_cfg (dict): Dictionary to construct and config act layer.
Default: dict(type='ReLU').
align_corners (bool): align_corners argument of F.interpolate.
Default: False.
init_cfg (dict or list[dict], optional): Initialization config dict.
Default: None.
"""
def __init__(self,
in_channels=(64, 256, 256),
out_channels=128,
conv_cfg=None,
norm_cfg=dict(type='BN'),
act_cfg=dict(type='ReLU'),
align_corners=False,
init_cfg=None):
super().__init__(init_cfg=init_cfg)
assert len(in_channels) == 3, 'Length of input channels \
must be 3!'
self.in_channels = in_channels
self.out_channels = out_channels
self.conv_cfg = conv_cfg
self.norm_cfg = norm_cfg
self.act_cfg = act_cfg
self.align_corners = align_corners
self.cff_24 = CascadeFeatureFusion(
self.in_channels[2],
self.in_channels[1],
self.out_channels,
conv_cfg=self.conv_cfg,
norm_cfg=self.norm_cfg,
act_cfg=self.act_cfg,
align_corners=self.align_corners)
self.cff_12 = CascadeFeatureFusion(
self.out_channels,
self.in_channels[0],
self.out_channels,
conv_cfg=self.conv_cfg,
norm_cfg=self.norm_cfg,
act_cfg=self.act_cfg,
align_corners=self.align_corners)
def forward(self, inputs):
assert len(inputs) == 3, 'Length of input feature \
maps must be 3!'
x_sub1, x_sub2, x_sub4 = inputs
x_cff_24, x_24 = self.cff_24(x_sub4, x_sub2)
x_cff_12, x_12 = self.cff_12(x_cff_24, x_sub1)
# Note: `x_cff_12` is used for decode_head,
# `x_24` and `x_12` are used for auxiliary head.
return x_24, x_12, x_cff_12