254 lines
9.0 KiB
Python

# All modification made by Kneron Corp.: Copyright (c) 2022 Kneron Corp.
# Copyright (c) OpenMMLab. All rights reserved.
import torch
import torch.nn as nn
import torch.utils.checkpoint as cp
from mmcv.cnn import build_conv_layer, build_norm_layer
from mmcv.runner import BaseModule
from torch.nn.modules.batchnorm import _BatchNorm
from mmcv.cnn import ConvModule
from ..builder import BACKBONES
class Focus(BaseModule):
"""Focus width and height information into channel space.
Args:
in_channels (int): The input channels of this Module.
out_channels (int): The output channels of this Module.
kernel_size (int): The kernel size of the convolution. Default: 1
stride (int): The stride of the convolution. Default: 1
conv_cfg (dict): Config dict for convolution layer. Default: None,
which means using conv2d.
norm_cfg (dict): Config dict for normalization layer.
Default: dict(type='BN', momentum=0.03, eps=0.001).
act_cfg (dict): Config dict for activation layer.
Default: dict(type='Swish').
"""
def __init__(self,
in_channels,
out_channels,
kernel_size=1,
stride=1,
conv_cfg=None,
norm_cfg=dict(type='BN', momentum=0.03, eps=0.001),
act_cfg=dict(type='LeakyReLU', negative_slope=0.1),
init_cfg=None):
super().__init__()
self.conv = ConvModule(
in_channels * 4,
out_channels,
kernel_size,
stride,
padding=(kernel_size - 1) // 2,
conv_cfg=conv_cfg,
norm_cfg=norm_cfg,
act_cfg=act_cfg)
def forward(self, x):
# shape of x (b,c,w,h) -> y(b,4c,w/2,h/2)
patch_top_left = x[..., ::2, ::2]
patch_top_right = x[..., ::2, 1::2]
patch_bot_left = x[..., 1::2, ::2]
patch_bot_right = x[..., 1::2, 1::2]
x = torch.cat(
(
patch_top_left,
patch_bot_left,
patch_top_right,
patch_bot_right,
),
dim=1,
)
return self.conv(x)
class VggLayer(BaseModule):
def __init__(self,
inplanes,
outplanes,
kernel_size=3,
stride=1,
dilation=1,
with_cp=False,
conv_cfg=None,
norm_cfg=dict(type='BN'),
init_cfg=None):
super(VggLayer, self).__init__(init_cfg)
self.inplanes = inplanes
self.stride = stride
self.dilation = dilation
self.with_cp = with_cp
self.conv_cfg = conv_cfg
self.norm_cfg = norm_cfg
self.conv1_stride = stride
self.norm1_name, norm1 = build_norm_layer(
norm_cfg, outplanes, postfix=1)
self.conv1 = build_conv_layer(
conv_cfg,
inplanes,
outplanes,
kernel_size=kernel_size,
stride=self.conv1_stride,
padding=(kernel_size - 1) // 2)
self.add_module(self.norm1_name, norm1)
self.LeakyRelu = nn.LeakyReLU(negative_slope=0.1, inplace=True)
@property
def norm1(self):
"""nn.Module: normalization layer after the first convolution layer"""
return getattr(self, self.norm1_name)
def forward(self, x):
"""Forward function."""
def _inner_forward(x):
out = self.conv1(x)
out = self.norm1(out)
out = self.LeakyRelu(out)
return out
if self.with_cp and x.requires_grad:
out = cp.checkpoint(_inner_forward, x)
else:
out = _inner_forward(x)
return out
@BACKBONES.register_module()
class FCOS_VGG(BaseModule):
"""
Args:
stem_channels (int | None): Number of stem channels. If not specified,
it will be the same as `base_channels`. Default: None.
base_channels (int): Number of base channels of res layer. Default: 64.
in_channels (int): Number of input image channels. Default: 3.
num_stages (int): Resnet stages. Default: 4.
strides (Sequence[int]): Strides of the first block of each stage.
dilations (Sequence[int]): Dilation of each stage.
out_indices (Sequence[int]): Output from which stages.
deep_stem (bool): Replace 7x7 conv in input stem with 3 3x3 conv
avg_down (bool): Use AvgPool instead of stride conv when
downsampling in the bottleneck.
frozen_stages (int): Stages to be frozen (stop grad and set eval mode).
-1 means not freezing any parameters.
norm_cfg (dict): Dictionary to construct and config norm layer.
norm_eval (bool): Whether to set norm layers to eval mode, namely,
freeze running stats (mean and var). Note: Effect on Batch Norm
and its variants only.
plugins (list[dict]): List of plugins for stages, each dict contains:
- cfg (dict, required): Cfg dict to build plugin.
- position (str, required): Position inside block to insert
plugin, options are 'after_conv1', 'after_conv2', 'after_conv3'.
- stages (tuple[bool], optional): Stages to apply plugin, length
should be same as 'num_stages'.
with_cp (bool): Use checkpoint or not. Using checkpoint will save some
memory while slowing down the training speed.
zero_init_residual (bool): Whether to use zero init for last norm layer
in resblocks to let them behave as identity.
pretrained (str, optional): model pretrained path. Default: None
init_cfg (dict or list[dict], optional): Initialization config dict.
Default: None
"""
def __init__(self,
in_channels=3,
stem_channels=None,
base_channels=32,
strides=(2, 1, 2, 2, 2),
dilations=(1, 1, 1, 1, 1),
out_indices=(0, 1, 2, 3),
out_planes=(64, 64, 128, 196, 128),
avg_down=False,
frozen_stages=-1,
conv_cfg=None,
norm_cfg=dict(type='BN', requires_grad=True),
act_cfg=dict(type='LeakyReLU', negative_slope=0.1),
norm_eval=True,
plugins=None,
with_cp=False,
zero_init_residual=True,
init_cfg=None):
super(FCOS_VGG, self).__init__(init_cfg)
self.zero_init_residual = zero_init_residual
if stem_channels is None:
stem_channels = base_channels
self.stem_channels = stem_channels
self.base_channels = base_channels
self.strides = strides
self.dilations = dilations
self.out_indices = out_indices
self.avg_down = avg_down
self.frozen_stages = frozen_stages
self.conv_cfg = conv_cfg
self.norm_cfg = norm_cfg
self.with_cp = with_cp
self.norm_eval = norm_eval
self.act_cfg = act_cfg
self.inplanes = stem_channels
self.stem = Focus(
in_channels,
self.base_channels,
kernel_size=3,
conv_cfg=conv_cfg,
norm_cfg=norm_cfg,
act_cfg=act_cfg)
self.vgg_layers = []
for i in range(len(out_planes)):
stride = strides[i]
dilation = dilations[i]
out_plane = out_planes[i]
vgg_layer = VggLayer(
inplanes=self.inplanes,
outplanes=out_plane,
stride=stride,
dilation=dilation,
with_cp=with_cp,
conv_cfg=conv_cfg,
norm_cfg=norm_cfg)
self.inplanes = out_plane
layer_name = f'layer{i + 1}'
self.add_module(layer_name, vgg_layer)
self.vgg_layers.append(layer_name)
self._freeze_stages()
@property
def norm1(self):
"""nn.Module: the normalization layer named "norm1" """
return getattr(self, self.norm1_name)
def _freeze_stages(self):
for i in range(1, self.frozen_stages + 1):
m = getattr(self, f'layer{i}')
m.eval()
for param in m.parameters():
param.requires_grad = False
def forward(self, x):
"""Forward function."""
x = self.stem(x)
outs = []
for i, layer_name in enumerate(self.vgg_layers):
vgg_layer = getattr(self, layer_name)
x = vgg_layer(x)
if i in self.out_indices:
outs.append(x)
return tuple(outs)
def train(self, mode=True):
"""Convert the model into training mode while keep normalization layer
freezed."""
super(FCOS_VGG, self).train(mode)
self._freeze_stages()
if mode and self.norm_eval:
for m in self.modules():
# trick: eval have effect on BatchNorm only
if isinstance(m, _BatchNorm):
m.eval()