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import torch
import torch.nn as nn
import torch.nn.functional as F
from mmcv.cnn import ConvModule
from .newcrf_utils import resize, normal_init
class PPM(nn.ModuleList):
"""Pooling Pyramid Module used in PSPNet.
Args:
pool_scales (tuple[int]): Pooling scales used in Pooling Pyramid
Module.
in_channels (int): Input channels.
channels (int): Channels after modules, before conv_seg.
conv_cfg (dict|None): Config of conv layers.
norm_cfg (dict|None): Config of norm layers.
act_cfg (dict): Config of activation layers.
align_corners (bool): align_corners argument of F.interpolate.
"""
def __init__(self, pool_scales, in_channels, channels, conv_cfg, norm_cfg,
act_cfg, align_corners):
super(PPM, self).__init__()
self.pool_scales = pool_scales
self.align_corners = align_corners
self.in_channels = in_channels
self.channels = channels
self.conv_cfg = conv_cfg
self.norm_cfg = norm_cfg
self.act_cfg = act_cfg
for pool_scale in pool_scales:
# == if batch size = 1, BN is not supported, change to GN
if pool_scale == 1: norm_cfg = dict(type='GN', requires_grad=True, num_groups=256)
self.append(
nn.Sequential(
nn.AdaptiveAvgPool2d(pool_scale),
ConvModule(
self.in_channels,
self.channels,
1,
conv_cfg=self.conv_cfg,
norm_cfg=norm_cfg,
act_cfg=self.act_cfg)))
def forward(self, x):
"""Forward function."""
ppm_outs = []
for ppm in self:
ppm_out = ppm(x)
upsampled_ppm_out = resize(
ppm_out,
size=x.size()[2:],
mode='bilinear',
align_corners=self.align_corners)
ppm_outs.append(upsampled_ppm_out)
return ppm_outs
class BaseDecodeHead(nn.Module):
"""Base class for BaseDecodeHead.
Args:
in_channels (int|Sequence[int]): Input channels.
channels (int): Channels after modules, before conv_seg.
num_classes (int): Number of classes.
dropout_ratio (float): Ratio of dropout layer. Default: 0.1.
conv_cfg (dict|None): Config of conv layers. Default: None.
norm_cfg (dict|None): Config of norm layers. Default: None.
act_cfg (dict): Config of activation layers.
Default: dict(type='ReLU')
in_index (int|Sequence[int]): Input feature index. Default: -1
input_transform (str|None): Transformation type of input features.
Options: 'resize_concat', 'multiple_select', None.
'resize_concat': Multiple feature maps will be resize to the
same size as first one and than concat together.
Usually used in FCN head of HRNet.
'multiple_select': Multiple feature maps will be bundle into
a list and passed into decode head.
None: Only one select feature map is allowed.
Default: None.
loss_decode (dict): Config of decode loss.
Default: dict(type='CrossEntropyLoss').
ignore_index (int | None): The label index to be ignored. When using
masked BCE loss, ignore_index should be set to None. Default: 255
sampler (dict|None): The config of segmentation map sampler.
Default: None.
align_corners (bool): align_corners argument of F.interpolate.
Default: False.
"""
def __init__(self,
in_channels,
channels,
*,
num_classes,
dropout_ratio=0.1,
conv_cfg=None,
norm_cfg=None,
act_cfg=dict(type='ReLU'),
in_index=-1,
input_transform=None,
loss_decode=dict(
type='CrossEntropyLoss',
use_sigmoid=False,
loss_weight=1.0),
ignore_index=255,
sampler=None,
align_corners=False):
super(BaseDecodeHead, self).__init__()
self._init_inputs(in_channels, in_index, input_transform)
self.channels = channels
self.num_classes = num_classes
self.dropout_ratio = dropout_ratio
self.conv_cfg = conv_cfg
self.norm_cfg = norm_cfg
self.act_cfg = act_cfg
self.in_index = in_index
# self.loss_decode = build_loss(loss_decode)
self.ignore_index = ignore_index
self.align_corners = align_corners
# if sampler is not None:
# self.sampler = build_pixel_sampler(sampler, context=self)
# else:
# self.sampler = None
# self.conv_seg = nn.Conv2d(channels, num_classes, kernel_size=1)
# self.conv1 = nn.Conv2d(channels, num_classes, 3, padding=1)
if dropout_ratio > 0:
self.dropout = nn.Dropout2d(dropout_ratio)
else:
self.dropout = None
self.fp16_enabled = False
def extra_repr(self):
"""Extra repr."""
s = f'input_transform={self.input_transform}, ' \
f'ignore_index={self.ignore_index}, ' \
f'align_corners={self.align_corners}'
return s
def _init_inputs(self, in_channels, in_index, input_transform):
"""Check and initialize input transforms.
The in_channels, in_index and input_transform must match.
Specifically, when input_transform is None, only single feature map
will be selected. So in_channels and in_index must be of type int.
When input_transform
Args:
in_channels (int|Sequence[int]): Input channels.
in_index (int|Sequence[int]): Input feature index.
input_transform (str|None): Transformation type of input features.
Options: 'resize_concat', 'multiple_select', None.
'resize_concat': Multiple feature maps will be resize to the
same size as first one and than concat together.
Usually used in FCN head of HRNet.
'multiple_select': Multiple feature maps will be bundle into
a list and passed into decode head.
None: Only one select feature map is allowed.
"""
if input_transform is not None:
assert input_transform in ['resize_concat', 'multiple_select']
self.input_transform = input_transform
self.in_index = in_index
if input_transform is not None:
assert isinstance(in_channels, (list, tuple))
assert isinstance(in_index, (list, tuple))
assert len(in_channels) == len(in_index)
if input_transform == 'resize_concat':
self.in_channels = sum(in_channels)
else:
self.in_channels = in_channels
else:
assert isinstance(in_channels, int)
assert isinstance(in_index, int)
self.in_channels = in_channels
def init_weights(self):
"""Initialize weights of classification layer."""
# normal_init(self.conv_seg, mean=0, std=0.01)
# normal_init(self.conv1, mean=0, std=0.01)
def _transform_inputs(self, inputs):
"""Transform inputs for decoder.
Args:
inputs (list[Tensor]): List of multi-level img features.
Returns:
Tensor: The transformed inputs
"""
if self.input_transform == 'resize_concat':
inputs = [inputs[i] for i in self.in_index]
upsampled_inputs = [
resize(
input=x,
size=inputs[0].shape[2:],
mode='bilinear',
align_corners=self.align_corners) for x in inputs
]
inputs = torch.cat(upsampled_inputs, dim=1)
elif self.input_transform == 'multiple_select':
inputs = [inputs[i] for i in self.in_index]
else:
inputs = inputs[self.in_index]
return inputs
def forward(self, inputs):
"""Placeholder of forward function."""
pass
def forward_train(self, inputs, img_metas, gt_semantic_seg, train_cfg):
"""Forward function for training.
Args:
inputs (list[Tensor]): List of multi-level img features.
img_metas (list[dict]): List of image info dict where each dict
has: 'img_shape', 'scale_factor', 'flip', and may also contain
'filename', 'ori_shape', 'pad_shape', and 'img_norm_cfg'.
For details on the values of these keys see
`mmseg/datasets/pipelines/formatting.py:Collect`.
gt_semantic_seg (Tensor): Semantic segmentation masks
used if the architecture supports semantic segmentation task.
train_cfg (dict): The training config.
Returns:
dict[str, Tensor]: a dictionary of loss components
"""
seg_logits = self.forward(inputs)
losses = self.losses(seg_logits, gt_semantic_seg)
return losses
def forward_test(self, inputs, img_metas, test_cfg):
"""Forward function for testing.
Args:
inputs (list[Tensor]): List of multi-level img features.
img_metas (list[dict]): List of image info dict where each dict
has: 'img_shape', 'scale_factor', 'flip', and may also contain
'filename', 'ori_shape', 'pad_shape', and 'img_norm_cfg'.
For details on the values of these keys see
`mmseg/datasets/pipelines/formatting.py:Collect`.
test_cfg (dict): The testing config.
Returns:
Tensor: Output segmentation map.
"""
return self.forward(inputs)
class UPerHead(BaseDecodeHead):
def __init__(self, pool_scales=(1, 2, 3, 6), **kwargs):
super(UPerHead, self).__init__(
input_transform='multiple_select', **kwargs)
# FPN Module
self.lateral_convs = nn.ModuleList()
self.fpn_convs = nn.ModuleList()
for in_channels in self.in_channels: # skip the top layer
l_conv = ConvModule(
in_channels,
self.channels,
1,
conv_cfg=self.conv_cfg,
norm_cfg=self.norm_cfg,
act_cfg=self.act_cfg,
inplace=True)
fpn_conv = ConvModule(
self.channels,
self.channels,
3,
padding=1,
conv_cfg=self.conv_cfg,
norm_cfg=self.norm_cfg,
act_cfg=self.act_cfg,
inplace=True)
self.lateral_convs.append(l_conv)
self.fpn_convs.append(fpn_conv)
def forward(self, inputs):
"""Forward function."""
inputs = self._transform_inputs(inputs)
# build laterals
laterals = [
lateral_conv(inputs[i])
for i, lateral_conv in enumerate(self.lateral_convs)
]
# laterals.append(self.psp_forward(inputs))
# build top-down path
used_backbone_levels = len(laterals)
for i in range(used_backbone_levels - 1, 0, -1):
prev_shape = laterals[i - 1].shape[2:]
laterals[i - 1] += resize(
laterals[i],
size=prev_shape,
mode='bilinear',
align_corners=self.align_corners)
# build outputs
fpn_outs = [
self.fpn_convs[i](laterals[i])
for i in range(used_backbone_levels - 1)
]
# append psp feature
fpn_outs.append(laterals[-1])
return fpn_outs[0]
class PSP(BaseDecodeHead):
"""Unified Perceptual Parsing for Scene Understanding.
This head is the implementation of `UPerNet
<https://arxiv.org/abs/1807.10221>`_.
Args:
pool_scales (tuple[int]): Pooling scales used in Pooling Pyramid
Module applied on the last feature. Default: (1, 2, 3, 6).
"""
def __init__(self, pool_scales=(1, 2, 3, 6), **kwargs):
super(PSP, self).__init__(
input_transform='multiple_select', **kwargs)
# PSP Module
self.psp_modules = PPM(
pool_scales,
self.in_channels[-1],
self.channels,
conv_cfg=self.conv_cfg,
norm_cfg=self.norm_cfg,
act_cfg=self.act_cfg,
align_corners=self.align_corners)
self.bottleneck = ConvModule(
self.in_channels[-1] + len(pool_scales) * self.channels,
self.channels,
3,
padding=1,
conv_cfg=self.conv_cfg,
norm_cfg=self.norm_cfg,
act_cfg=self.act_cfg)
def psp_forward(self, inputs):
"""Forward function of PSP module."""
x = inputs[-1]
psp_outs = [x]
psp_outs.extend(self.psp_modules(x))
psp_outs = torch.cat(psp_outs, dim=1)
output = self.bottleneck(psp_outs)
return output
def forward(self, inputs):
"""Forward function."""
inputs = self._transform_inputs(inputs)
return self.psp_forward(inputs)
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