# 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 paddle.nn import AdaptiveAvgPool2D, Linear from paddle.regularizer import L2Decay from paddle import ParamAttr from paddle.nn.initializer import Normal, Uniform from numbers import Integral import math from ppdet.core.workspace import register from ..shape_spec import ShapeSpec __all__ = ['HRNet'] class ConvNormLayer(nn.Layer): def __init__(self, ch_in, ch_out, filter_size, stride=1, norm_type='bn', norm_groups=32, use_dcn=False, norm_decay=0., freeze_norm=False, act=None, name=None): super(ConvNormLayer, self).__init__() assert norm_type in ['bn', 'sync_bn', 'gn'] self.act = act self.conv = nn.Conv2D( in_channels=ch_in, out_channels=ch_out, kernel_size=filter_size, stride=stride, padding=(filter_size - 1) // 2, groups=1, weight_attr=ParamAttr(initializer=Normal( mean=0., std=0.01)), bias_attr=False) norm_lr = 0. if freeze_norm else 1. param_attr = ParamAttr( learning_rate=norm_lr, regularizer=L2Decay(norm_decay)) bias_attr = ParamAttr( learning_rate=norm_lr, regularizer=L2Decay(norm_decay)) global_stats = True if freeze_norm else None if norm_type in ['bn', 'sync_bn']: self.norm = nn.BatchNorm2D( ch_out, weight_attr=param_attr, bias_attr=bias_attr, use_global_stats=global_stats) elif norm_type == 'gn': self.norm = nn.GroupNorm( num_groups=norm_groups, num_channels=ch_out, weight_attr=param_attr, bias_attr=bias_attr) norm_params = self.norm.parameters() if freeze_norm: for param in norm_params: param.stop_gradient = True def forward(self, inputs): out = self.conv(inputs) out = self.norm(out) if self.act == 'relu': out = F.relu(out) return out class Layer1(nn.Layer): def __init__(self, num_channels, has_se=False, norm_decay=0., freeze_norm=True, name=None): super(Layer1, self).__init__() self.bottleneck_block_list = [] for i in range(4): bottleneck_block = self.add_sublayer( "block_{}_{}".format(name, i + 1), BottleneckBlock( num_channels=num_channels if i == 0 else 256, num_filters=64, has_se=has_se, stride=1, downsample=True if i == 0 else False, norm_decay=norm_decay, freeze_norm=freeze_norm, name=name + '_' + str(i + 1))) self.bottleneck_block_list.append(bottleneck_block) def forward(self, input): conv = input for block_func in self.bottleneck_block_list: conv = block_func(conv) return conv class TransitionLayer(nn.Layer): def __init__(self, in_channels, out_channels, norm_decay=0., freeze_norm=True, name=None): super(TransitionLayer, self).__init__() num_in = len(in_channels) num_out = len(out_channels) out = [] self.conv_bn_func_list = [] for i in range(num_out): residual = None if i < num_in: if in_channels[i] != out_channels[i]: residual = self.add_sublayer( "transition_{}_layer_{}".format(name, i + 1), ConvNormLayer( ch_in=in_channels[i], ch_out=out_channels[i], filter_size=3, norm_decay=norm_decay, freeze_norm=freeze_norm, act='relu', name=name + '_layer_' + str(i + 1))) else: residual = self.add_sublayer( "transition_{}_layer_{}".format(name, i + 1), ConvNormLayer( ch_in=in_channels[-1], ch_out=out_channels[i], filter_size=3, stride=2, norm_decay=norm_decay, freeze_norm=freeze_norm, act='relu', name=name + '_layer_' + str(i + 1))) self.conv_bn_func_list.append(residual) def forward(self, input): outs = [] for idx, conv_bn_func in enumerate(self.conv_bn_func_list): if conv_bn_func is None: outs.append(input[idx]) else: if idx < len(input): outs.append(conv_bn_func(input[idx])) else: outs.append(conv_bn_func(input[-1])) return outs class Branches(nn.Layer): def __init__(self, block_num, in_channels, out_channels, has_se=False, norm_decay=0., freeze_norm=True, name=None): super(Branches, self).__init__() self.basic_block_list = [] for i in range(len(out_channels)): self.basic_block_list.append([]) for j in range(block_num): in_ch = in_channels[i] if j == 0 else out_channels[i] basic_block_func = self.add_sublayer( "bb_{}_branch_layer_{}_{}".format(name, i + 1, j + 1), BasicBlock( num_channels=in_ch, num_filters=out_channels[i], has_se=has_se, norm_decay=norm_decay, freeze_norm=freeze_norm, name=name + '_branch_layer_' + str(i + 1) + '_' + str(j + 1))) self.basic_block_list[i].append(basic_block_func) def forward(self, inputs): outs = [] for idx, input in enumerate(inputs): conv = input basic_block_list = self.basic_block_list[idx] for basic_block_func in basic_block_list: conv = basic_block_func(conv) outs.append(conv) return outs class BottleneckBlock(nn.Layer): def __init__(self, num_channels, num_filters, has_se, stride=1, downsample=False, norm_decay=0., freeze_norm=True, name=None): super(BottleneckBlock, self).__init__() self.has_se = has_se self.downsample = downsample self.conv1 = ConvNormLayer( ch_in=num_channels, ch_out=num_filters, filter_size=1, norm_decay=norm_decay, freeze_norm=freeze_norm, act="relu", name=name + "_conv1") self.conv2 = ConvNormLayer( ch_in=num_filters, ch_out=num_filters, filter_size=3, stride=stride, norm_decay=norm_decay, freeze_norm=freeze_norm, act="relu", name=name + "_conv2") self.conv3 = ConvNormLayer( ch_in=num_filters, ch_out=num_filters * 4, filter_size=1, norm_decay=norm_decay, freeze_norm=freeze_norm, act=None, name=name + "_conv3") if self.downsample: self.conv_down = ConvNormLayer( ch_in=num_channels, ch_out=num_filters * 4, filter_size=1, norm_decay=norm_decay, freeze_norm=freeze_norm, act=None, name=name + "_downsample") if self.has_se: self.se = SELayer( num_channels=num_filters * 4, num_filters=num_filters * 4, reduction_ratio=16, name='fc' + name) def forward(self, input): residual = input conv1 = self.conv1(input) conv2 = self.conv2(conv1) conv3 = self.conv3(conv2) if self.downsample: residual = self.conv_down(input) if self.has_se: conv3 = self.se(conv3) y = paddle.add(x=residual, y=conv3) y = F.relu(y) return y class BasicBlock(nn.Layer): def __init__(self, num_channels, num_filters, stride=1, has_se=False, downsample=False, norm_decay=0., freeze_norm=True, name=None): super(BasicBlock, self).__init__() self.has_se = has_se self.downsample = downsample self.conv1 = ConvNormLayer( ch_in=num_channels, ch_out=num_filters, filter_size=3, norm_decay=norm_decay, freeze_norm=freeze_norm, stride=stride, act="relu", name=name + "_conv1") self.conv2 = ConvNormLayer( ch_in=num_filters, ch_out=num_filters, filter_size=3, norm_decay=norm_decay, freeze_norm=freeze_norm, stride=1, act=None, name=name + "_conv2") if self.downsample: self.conv_down = ConvNormLayer( ch_in=num_channels, ch_out=num_filters * 4, filter_size=1, norm_decay=norm_decay, freeze_norm=freeze_norm, act=None, name=name + "_downsample") if self.has_se: self.se = SELayer( num_channels=num_filters, num_filters=num_filters, reduction_ratio=16, name='fc' + name) def forward(self, input): residual = input conv1 = self.conv1(input) conv2 = self.conv2(conv1) if self.downsample: residual = self.conv_down(input) if self.has_se: conv2 = self.se(conv2) y = paddle.add(x=residual, y=conv2) y = F.relu(y) return y class SELayer(nn.Layer): def __init__(self, num_channels, num_filters, reduction_ratio, name=None): super(SELayer, self).__init__() self.pool2d_gap = AdaptiveAvgPool2D(1) self._num_channels = num_channels med_ch = int(num_channels / reduction_ratio) stdv = 1.0 / math.sqrt(num_channels * 1.0) self.squeeze = Linear( num_channels, med_ch, weight_attr=ParamAttr(initializer=Uniform(-stdv, stdv))) stdv = 1.0 / math.sqrt(med_ch * 1.0) self.excitation = Linear( med_ch, num_filters, weight_attr=ParamAttr(initializer=Uniform(-stdv, stdv))) def forward(self, input): pool = self.pool2d_gap(input) pool = paddle.squeeze(pool, axis=[2, 3]) squeeze = self.squeeze(pool) squeeze = F.relu(squeeze) excitation = self.excitation(squeeze) excitation = F.sigmoid(excitation) excitation = paddle.unsqueeze(excitation, axis=[2, 3]) out = input * excitation return out class Stage(nn.Layer): def __init__(self, num_channels, num_modules, num_filters, has_se=False, norm_decay=0., freeze_norm=True, multi_scale_output=True, name=None): super(Stage, self).__init__() self._num_modules = num_modules self.stage_func_list = [] for i in range(num_modules): if i == num_modules - 1 and not multi_scale_output: stage_func = self.add_sublayer( "stage_{}_{}".format(name, i + 1), HighResolutionModule( num_channels=num_channels, num_filters=num_filters, has_se=has_se, norm_decay=norm_decay, freeze_norm=freeze_norm, multi_scale_output=False, name=name + '_' + str(i + 1))) else: stage_func = self.add_sublayer( "stage_{}_{}".format(name, i + 1), HighResolutionModule( num_channels=num_channels, num_filters=num_filters, has_se=has_se, norm_decay=norm_decay, freeze_norm=freeze_norm, name=name + '_' + str(i + 1))) self.stage_func_list.append(stage_func) def forward(self, input): out = input for idx in range(self._num_modules): out = self.stage_func_list[idx](out) return out class HighResolutionModule(nn.Layer): def __init__(self, num_channels, num_filters, has_se=False, multi_scale_output=True, norm_decay=0., freeze_norm=True, name=None): super(HighResolutionModule, self).__init__() self.branches_func = Branches( block_num=4, in_channels=num_channels, out_channels=num_filters, has_se=has_se, norm_decay=norm_decay, freeze_norm=freeze_norm, name=name) self.fuse_func = FuseLayers( in_channels=num_filters, out_channels=num_filters, multi_scale_output=multi_scale_output, norm_decay=norm_decay, freeze_norm=freeze_norm, name=name) def forward(self, input): out = self.branches_func(input) out = self.fuse_func(out) return out class FuseLayers(nn.Layer): def __init__(self, in_channels, out_channels, multi_scale_output=True, norm_decay=0., freeze_norm=True, name=None): super(FuseLayers, self).__init__() self._actual_ch = len(in_channels) if multi_scale_output else 1 self._in_channels = in_channels self.residual_func_list = [] for i in range(self._actual_ch): for j in range(len(in_channels)): residual_func = None if j > i: residual_func = self.add_sublayer( "residual_{}_layer_{}_{}".format(name, i + 1, j + 1), ConvNormLayer( ch_in=in_channels[j], ch_out=out_channels[i], filter_size=1, stride=1, act=None, norm_decay=norm_decay, freeze_norm=freeze_norm, name=name + '_layer_' + str(i + 1) + '_' + str(j + 1))) self.residual_func_list.append(residual_func) elif j < i: pre_num_filters = in_channels[j] for k in range(i - j): if k == i - j - 1: residual_func = self.add_sublayer( "residual_{}_layer_{}_{}_{}".format( name, i + 1, j + 1, k + 1), ConvNormLayer( ch_in=pre_num_filters, ch_out=out_channels[i], filter_size=3, stride=2, norm_decay=norm_decay, freeze_norm=freeze_norm, act=None, name=name + '_layer_' + str(i + 1) + '_' + str(j + 1) + '_' + str(k + 1))) pre_num_filters = out_channels[i] else: residual_func = self.add_sublayer( "residual_{}_layer_{}_{}_{}".format( name, i + 1, j + 1, k + 1), ConvNormLayer( ch_in=pre_num_filters, ch_out=out_channels[j], filter_size=3, stride=2, norm_decay=norm_decay, freeze_norm=freeze_norm, act="relu", name=name + '_layer_' + str(i + 1) + '_' + str(j + 1) + '_' + str(k + 1))) pre_num_filters = out_channels[j] self.residual_func_list.append(residual_func) def forward(self, input): outs = [] residual_func_idx = 0 for i in range(self._actual_ch): residual = input[i] for j in range(len(self._in_channels)): if j > i: y = self.residual_func_list[residual_func_idx](input[j]) residual_func_idx += 1 y = F.interpolate(y, scale_factor=2**(j - i)) residual = paddle.add(x=residual, y=y) elif j < i: y = input[j] for k in range(i - j): y = self.residual_func_list[residual_func_idx](y) residual_func_idx += 1 residual = paddle.add(x=residual, y=y) residual = F.relu(residual) outs.append(residual) return outs @register class HRNet(nn.Layer): """ HRNet, see https://arxiv.org/abs/1908.07919 Args: width (int): the width of HRNet has_se (bool): whether to add SE block for each stage freeze_at (int): the stage to freeze freeze_norm (bool): whether to freeze norm in HRNet norm_decay (float): weight decay for normalization layer weights return_idx (List): the stage to return upsample (bool): whether to upsample and concat the backbone feats """ def __init__(self, width=18, has_se=False, freeze_at=0, freeze_norm=True, norm_decay=0., return_idx=[0, 1, 2, 3], upsample=False): super(HRNet, self).__init__() self.width = width self.has_se = has_se if isinstance(return_idx, Integral): return_idx = [return_idx] assert len(return_idx) > 0, "need one or more return index" self.freeze_at = freeze_at self.return_idx = return_idx self.upsample = upsample self.channels = { 18: [[18, 36], [18, 36, 72], [18, 36, 72, 144]], 30: [[30, 60], [30, 60, 120], [30, 60, 120, 240]], 32: [[32, 64], [32, 64, 128], [32, 64, 128, 256]], 40: [[40, 80], [40, 80, 160], [40, 80, 160, 320]], 44: [[44, 88], [44, 88, 176], [44, 88, 176, 352]], 48: [[48, 96], [48, 96, 192], [48, 96, 192, 384]], 60: [[60, 120], [60, 120, 240], [60, 120, 240, 480]], 64: [[64, 128], [64, 128, 256], [64, 128, 256, 512]] } channels_2, channels_3, channels_4 = self.channels[width] num_modules_2, num_modules_3, num_modules_4 = 1, 4, 3 self._out_channels = [sum(channels_4)] if self.upsample else channels_4 self._out_strides = [4] if self.upsample else [4, 8, 16, 32] self.conv_layer1_1 = ConvNormLayer( ch_in=3, ch_out=64, filter_size=3, stride=2, norm_decay=norm_decay, freeze_norm=freeze_norm, act='relu', name="layer1_1") self.conv_layer1_2 = ConvNormLayer( ch_in=64, ch_out=64, filter_size=3, stride=2, norm_decay=norm_decay, freeze_norm=freeze_norm, act='relu', name="layer1_2") self.la1 = Layer1( num_channels=64, has_se=has_se, norm_decay=norm_decay, freeze_norm=freeze_norm, name="layer2") self.tr1 = TransitionLayer( in_channels=[256], out_channels=channels_2, norm_decay=norm_decay, freeze_norm=freeze_norm, name="tr1") self.st2 = Stage( num_channels=channels_2, num_modules=num_modules_2, num_filters=channels_2, has_se=self.has_se, norm_decay=norm_decay, freeze_norm=freeze_norm, name="st2") self.tr2 = TransitionLayer( in_channels=channels_2, out_channels=channels_3, norm_decay=norm_decay, freeze_norm=freeze_norm, name="tr2") self.st3 = Stage( num_channels=channels_3, num_modules=num_modules_3, num_filters=channels_3, has_se=self.has_se, norm_decay=norm_decay, freeze_norm=freeze_norm, name="st3") self.tr3 = TransitionLayer( in_channels=channels_3, out_channels=channels_4, norm_decay=norm_decay, freeze_norm=freeze_norm, name="tr3") self.st4 = Stage( num_channels=channels_4, num_modules=num_modules_4, num_filters=channels_4, has_se=self.has_se, norm_decay=norm_decay, freeze_norm=freeze_norm, multi_scale_output=len(return_idx) > 1, name="st4") def forward(self, inputs): x = inputs['image'] conv1 = self.conv_layer1_1(x) conv2 = self.conv_layer1_2(conv1) la1 = self.la1(conv2) tr1 = self.tr1([la1]) st2 = self.st2(tr1) tr2 = self.tr2(st2) st3 = self.st3(tr2) tr3 = self.tr3(st3) st4 = self.st4(tr3) if self.upsample: # Upsampling x0_h, x0_w = st4[0].shape[2:4] x1 = F.upsample(st4[1], size=(x0_h, x0_w), mode='bilinear') x2 = F.upsample(st4[2], size=(x0_h, x0_w), mode='bilinear') x3 = F.upsample(st4[3], size=(x0_h, x0_w), mode='bilinear') x = paddle.concat([st4[0], x1, x2, x3], 1) return x res = [] for i, layer in enumerate(st4): if i == self.freeze_at: layer.stop_gradient = True if i in self.return_idx: res.append(layer) return res @property def out_shape(self): if self.upsample: self.return_idx = [0] return [ ShapeSpec( channels=self._out_channels[i], stride=self._out_strides[i]) for i in self.return_idx ]