PulseFocusPlatform/ppdet/modeling/heads/centernet_head.py

193 lines
6.9 KiB
Python

# Copyright (c) 2021 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 math
import paddle
import paddle.nn as nn
import paddle.nn.functional as F
from paddle.nn.initializer import KaimingUniform
from ppdet.core.workspace import register
from ppdet.modeling.losses import CTFocalLoss
class ConvLayer(nn.Layer):
def __init__(self,
ch_in,
ch_out,
kernel_size,
stride=1,
padding=0,
dilation=1,
groups=1,
bias=False):
super(ConvLayer, self).__init__()
bias_attr = False
fan_in = ch_in * kernel_size**2
bound = 1 / math.sqrt(fan_in)
param_attr = paddle.ParamAttr(initializer=KaimingUniform())
if bias:
bias_attr = paddle.ParamAttr(
initializer=nn.initializer.Uniform(-bound, bound))
self.conv = nn.Conv2D(
in_channels=ch_in,
out_channels=ch_out,
kernel_size=kernel_size,
stride=stride,
padding=padding,
dilation=dilation,
groups=groups,
weight_attr=param_attr,
bias_attr=bias_attr)
def forward(self, inputs):
out = self.conv(inputs)
return out
@register
class CenterNetHead(nn.Layer):
"""
Args:
in_channels (int): the channel number of input to CenterNetHead.
num_classes (int): the number of classes, 80 by default.
head_planes (int): the channel number in all head, 256 by default.
heatmap_weight (float): the weight of heatmap loss, 1 by default.
regress_ltrb (bool): whether to regress left/top/right/bottom or
width/height for a box, true by default
size_weight (float): the weight of box size loss, 0.1 by default.
offset_weight (float): the weight of center offset loss, 1 by default.
"""
__shared__ = ['num_classes']
def __init__(self,
in_channels,
num_classes=80,
head_planes=256,
heatmap_weight=1,
regress_ltrb=True,
size_weight=0.1,
offset_weight=1):
super(CenterNetHead, self).__init__()
self.weights = {
'heatmap': heatmap_weight,
'size': size_weight,
'offset': offset_weight
}
self.heatmap = nn.Sequential(
ConvLayer(
in_channels, head_planes, kernel_size=3, padding=1, bias=True),
nn.ReLU(),
ConvLayer(
head_planes,
num_classes,
kernel_size=1,
stride=1,
padding=0,
bias=True))
self.heatmap[2].conv.bias[:] = -2.19
self.size = nn.Sequential(
ConvLayer(
in_channels, head_planes, kernel_size=3, padding=1, bias=True),
nn.ReLU(),
ConvLayer(
head_planes,
4 if regress_ltrb else 2,
kernel_size=1,
stride=1,
padding=0,
bias=True))
self.offset = nn.Sequential(
ConvLayer(
in_channels, head_planes, kernel_size=3, padding=1, bias=True),
nn.ReLU(),
ConvLayer(
head_planes, 2, kernel_size=1, stride=1, padding=0, bias=True))
self.focal_loss = CTFocalLoss()
@classmethod
def from_config(cls, cfg, input_shape):
if isinstance(input_shape, (list, tuple)):
input_shape = input_shape[0]
return {'in_channels': input_shape.channels}
def forward(self, feat, inputs):
heatmap = self.heatmap(feat)
size = self.size(feat)
offset = self.offset(feat)
if self.training:
loss = self.get_loss(heatmap, size, offset, self.weights, inputs)
return loss
else:
heatmap = F.sigmoid(heatmap)
return {'heatmap': heatmap, 'size': size, 'offset': offset}
def get_loss(self, heatmap, size, offset, weights, inputs):
heatmap_target = inputs['heatmap']
size_target = inputs['size']
offset_target = inputs['offset']
index = inputs['index']
mask = inputs['index_mask']
heatmap = paddle.clip(F.sigmoid(heatmap), 1e-4, 1 - 1e-4)
heatmap_loss = self.focal_loss(heatmap, heatmap_target)
size = paddle.transpose(size, perm=[0, 2, 3, 1])
size_n, size_h, size_w, size_c = size.shape
size = paddle.reshape(size, shape=[size_n, -1, size_c])
index = paddle.unsqueeze(index, 2)
batch_inds = list()
for i in range(size_n):
batch_ind = paddle.full(
shape=[1, index.shape[1], 1], fill_value=i, dtype='int64')
batch_inds.append(batch_ind)
batch_inds = paddle.concat(batch_inds, axis=0)
index = paddle.concat(x=[batch_inds, index], axis=2)
pos_size = paddle.gather_nd(size, index=index)
mask = paddle.unsqueeze(mask, axis=2)
size_mask = paddle.expand_as(mask, pos_size)
size_mask = paddle.cast(size_mask, dtype=pos_size.dtype)
pos_num = size_mask.sum()
size_mask.stop_gradient = True
size_target.stop_gradient = True
size_loss = F.l1_loss(
pos_size * size_mask, size_target * size_mask, reduction='sum')
size_loss = size_loss / (pos_num + 1e-4)
offset = paddle.transpose(offset, perm=[0, 2, 3, 1])
offset_n, offset_h, offset_w, offset_c = offset.shape
offset = paddle.reshape(offset, shape=[offset_n, -1, offset_c])
pos_offset = paddle.gather_nd(offset, index=index)
offset_mask = paddle.expand_as(mask, pos_offset)
offset_mask = paddle.cast(offset_mask, dtype=pos_offset.dtype)
pos_num = offset_mask.sum()
offset_mask.stop_gradient = True
offset_target.stop_gradient = True
offset_loss = F.l1_loss(
pos_offset * offset_mask,
offset_target * offset_mask,
reduction='sum')
offset_loss = offset_loss / (pos_num + 1e-4)
det_loss = weights['heatmap'] * heatmap_loss + weights[
'size'] * size_loss + weights['offset'] * offset_loss
return {
'det_loss': det_loss,
'heatmap_loss': heatmap_loss,
'size_loss': size_loss,
'offset_loss': offset_loss
}