PulseFocusPlatform/ppdet/modeling/backbones/darknet.py

341 lines
11 KiB
Python

# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import paddle
import paddle.nn as nn
import paddle.nn.functional as F
from ppdet.core.workspace import register, serializable
from ppdet.modeling.ops import batch_norm, mish
from ..shape_spec import ShapeSpec
__all__ = ['DarkNet', 'ConvBNLayer']
class ConvBNLayer(nn.Layer):
def __init__(self,
ch_in,
ch_out,
filter_size=3,
stride=1,
groups=1,
padding=0,
norm_type='bn',
norm_decay=0.,
act="leaky",
freeze_norm=False,
data_format='NCHW',
name=''):
"""
conv + bn + activation layer
Args:
ch_in (int): input channel
ch_out (int): output channel
filter_size (int): filter size, default 3
stride (int): stride, default 1
groups (int): number of groups of conv layer, default 1
padding (int): padding size, default 0
norm_type (str): batch norm type, default bn
norm_decay (str): decay for weight and bias of batch norm layer, default 0.
act (str): activation function type, default 'leaky', which means leaky_relu
freeze_norm (bool): whether to freeze norm, default False
data_format (str): data format, NCHW or NHWC
"""
super(ConvBNLayer, self).__init__()
self.conv = nn.Conv2D(
in_channels=ch_in,
out_channels=ch_out,
kernel_size=filter_size,
stride=stride,
padding=padding,
groups=groups,
data_format=data_format,
bias_attr=False)
self.batch_norm = batch_norm(
ch_out,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format)
self.act = act
def forward(self, inputs):
out = self.conv(inputs)
out = self.batch_norm(out)
if self.act == 'leaky':
out = F.leaky_relu(out, 0.1)
elif self.act == 'mish':
out = mish(out)
return out
class DownSample(nn.Layer):
def __init__(self,
ch_in,
ch_out,
filter_size=3,
stride=2,
padding=1,
norm_type='bn',
norm_decay=0.,
freeze_norm=False,
data_format='NCHW'):
"""
downsample layer
Args:
ch_in (int): input channel
ch_out (int): output channel
filter_size (int): filter size, default 3
stride (int): stride, default 2
padding (int): padding size, default 1
norm_type (str): batch norm type, default bn
norm_decay (str): decay for weight and bias of batch norm layer, default 0.
freeze_norm (bool): whether to freeze norm, default False
data_format (str): data format, NCHW or NHWC
"""
super(DownSample, self).__init__()
self.conv_bn_layer = ConvBNLayer(
ch_in=ch_in,
ch_out=ch_out,
filter_size=filter_size,
stride=stride,
padding=padding,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format)
self.ch_out = ch_out
def forward(self, inputs):
out = self.conv_bn_layer(inputs)
return out
class BasicBlock(nn.Layer):
def __init__(self,
ch_in,
ch_out,
norm_type='bn',
norm_decay=0.,
freeze_norm=False,
data_format='NCHW'):
"""
BasicBlock layer of DarkNet
Args:
ch_in (int): input channel
ch_out (int): output channel
norm_type (str): batch norm type, default bn
norm_decay (str): decay for weight and bias of batch norm layer, default 0.
freeze_norm (bool): whether to freeze norm, default False
data_format (str): data format, NCHW or NHWC
"""
super(BasicBlock, self).__init__()
self.conv1 = ConvBNLayer(
ch_in=ch_in,
ch_out=ch_out,
filter_size=1,
stride=1,
padding=0,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format)
self.conv2 = ConvBNLayer(
ch_in=ch_out,
ch_out=ch_out * 2,
filter_size=3,
stride=1,
padding=1,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format)
def forward(self, inputs):
conv1 = self.conv1(inputs)
conv2 = self.conv2(conv1)
out = paddle.add(x=inputs, y=conv2)
return out
class Blocks(nn.Layer):
def __init__(self,
ch_in,
ch_out,
count,
norm_type='bn',
norm_decay=0.,
freeze_norm=False,
name=None,
data_format='NCHW'):
"""
Blocks layer, which consist of some BaickBlock layers
Args:
ch_in (int): input channel
ch_out (int): output channel
count (int): number of BasicBlock layer
norm_type (str): batch norm type, default bn
norm_decay (str): decay for weight and bias of batch norm layer, default 0.
freeze_norm (bool): whether to freeze norm, default False
name (str): layer name
data_format (str): data format, NCHW or NHWC
"""
super(Blocks, self).__init__()
self.basicblock0 = BasicBlock(
ch_in,
ch_out,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format)
self.res_out_list = []
for i in range(1, count):
block_name = '{}.{}'.format(name, i)
res_out = self.add_sublayer(
block_name,
BasicBlock(
ch_out * 2,
ch_out,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format))
self.res_out_list.append(res_out)
self.ch_out = ch_out
def forward(self, inputs):
y = self.basicblock0(inputs)
for basic_block_i in self.res_out_list:
y = basic_block_i(y)
return y
DarkNet_cfg = {53: ([1, 2, 8, 8, 4])}
@register
@serializable
class DarkNet(nn.Layer):
__shared__ = ['norm_type', 'data_format']
def __init__(self,
depth=53,
freeze_at=-1,
return_idx=[2, 3, 4],
num_stages=5,
norm_type='bn',
norm_decay=0.,
freeze_norm=False,
data_format='NCHW'):
"""
Darknet, see https://pjreddie.com/darknet/yolo/
Args:
depth (int): depth of network
freeze_at (int): freeze the backbone at which stage
filter_size (int): filter size, default 3
return_idx (list): index of stages whose feature maps are returned
norm_type (str): batch norm type, default bn
norm_decay (str): decay for weight and bias of batch norm layer, default 0.
data_format (str): data format, NCHW or NHWC
"""
super(DarkNet, self).__init__()
self.depth = depth
self.freeze_at = freeze_at
self.return_idx = return_idx
self.num_stages = num_stages
self.stages = DarkNet_cfg[self.depth][0:num_stages]
self.conv0 = ConvBNLayer(
ch_in=3,
ch_out=32,
filter_size=3,
stride=1,
padding=1,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format)
self.downsample0 = DownSample(
ch_in=32,
ch_out=32 * 2,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format)
self._out_channels = []
self.darknet_conv_block_list = []
self.downsample_list = []
ch_in = [64, 128, 256, 512, 1024]
for i, stage in enumerate(self.stages):
name = 'stage.{}'.format(i)
conv_block = self.add_sublayer(
name,
Blocks(
int(ch_in[i]),
32 * (2**i),
stage,
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format,
name=name))
self.darknet_conv_block_list.append(conv_block)
if i in return_idx:
self._out_channels.append(64 * (2**i))
for i in range(num_stages - 1):
down_name = 'stage.{}.downsample'.format(i)
downsample = self.add_sublayer(
down_name,
DownSample(
ch_in=32 * (2**(i + 1)),
ch_out=32 * (2**(i + 2)),
norm_type=norm_type,
norm_decay=norm_decay,
freeze_norm=freeze_norm,
data_format=data_format))
self.downsample_list.append(downsample)
def forward(self, inputs):
x = inputs['image']
out = self.conv0(x)
out = self.downsample0(out)
blocks = []
for i, conv_block_i in enumerate(self.darknet_conv_block_list):
out = conv_block_i(out)
if i == self.freeze_at:
out.stop_gradient = True
if i in self.return_idx:
blocks.append(out)
if i < self.num_stages - 1:
out = self.downsample_list[i](out)
return blocks
@property
def out_shape(self):
return [ShapeSpec(channels=c) for c in self._out_channels]