import torch.nn as nn from annotator.mmpkg.mmcv.cnn import (build_conv_layer, build_norm_layer, constant_init, kaiming_init) from annotator.mmpkg.mmcv.runner import load_checkpoint from annotator.mmpkg.mmcv.utils.parrots_wrapper import _BatchNorm from annotator.mmpkg.mmseg.ops import Upsample, resize from annotator.mmpkg.mmseg.utils import get_root_logger from ..builder import BACKBONES from .resnet import BasicBlock, Bottleneck class HRModule(nn.Module): """High-Resolution Module for HRNet. In this module, every branch has 4 BasicBlocks/Bottlenecks. Fusion/Exchange is in this module. """ def __init__(self, num_branches, blocks, num_blocks, in_channels, num_channels, multiscale_output=True, with_cp=False, conv_cfg=None, norm_cfg=dict(type='BN', requires_grad=True)): super(HRModule, self).__init__() self._check_branches(num_branches, num_blocks, in_channels, num_channels) self.in_channels = in_channels self.num_branches = num_branches self.multiscale_output = multiscale_output self.norm_cfg = norm_cfg self.conv_cfg = conv_cfg self.with_cp = with_cp self.branches = self._make_branches(num_branches, blocks, num_blocks, num_channels) self.fuse_layers = self._make_fuse_layers() self.relu = nn.ReLU(inplace=False) def _check_branches(self, num_branches, num_blocks, in_channels, num_channels): """Check branches configuration.""" if num_branches != len(num_blocks): error_msg = f'NUM_BRANCHES({num_branches}) <> NUM_BLOCKS(' \ f'{len(num_blocks)})' raise ValueError(error_msg) if num_branches != len(num_channels): error_msg = f'NUM_BRANCHES({num_branches}) <> NUM_CHANNELS(' \ f'{len(num_channels)})' raise ValueError(error_msg) if num_branches != len(in_channels): error_msg = f'NUM_BRANCHES({num_branches}) <> NUM_INCHANNELS(' \ f'{len(in_channels)})' raise ValueError(error_msg) def _make_one_branch(self, branch_index, block, num_blocks, num_channels, stride=1): """Build one branch.""" downsample = None if stride != 1 or \ self.in_channels[branch_index] != \ num_channels[branch_index] * block.expansion: downsample = nn.Sequential( build_conv_layer( self.conv_cfg, self.in_channels[branch_index], num_channels[branch_index] * block.expansion, kernel_size=1, stride=stride, bias=False), build_norm_layer(self.norm_cfg, num_channels[branch_index] * block.expansion)[1]) layers = [] layers.append( block( self.in_channels[branch_index], num_channels[branch_index], stride, downsample=downsample, with_cp=self.with_cp, norm_cfg=self.norm_cfg, conv_cfg=self.conv_cfg)) self.in_channels[branch_index] = \ num_channels[branch_index] * block.expansion for i in range(1, num_blocks[branch_index]): layers.append( block( self.in_channels[branch_index], num_channels[branch_index], with_cp=self.with_cp, norm_cfg=self.norm_cfg, conv_cfg=self.conv_cfg)) return nn.Sequential(*layers) def _make_branches(self, num_branches, block, num_blocks, num_channels): """Build multiple branch.""" branches = [] for i in range(num_branches): branches.append( self._make_one_branch(i, block, num_blocks, num_channels)) return nn.ModuleList(branches) def _make_fuse_layers(self): """Build fuse layer.""" if self.num_branches == 1: return None num_branches = self.num_branches in_channels = self.in_channels fuse_layers = [] num_out_branches = num_branches if self.multiscale_output else 1 for i in range(num_out_branches): fuse_layer = [] for j in range(num_branches): if j > i: fuse_layer.append( nn.Sequential( build_conv_layer( self.conv_cfg, in_channels[j], in_channels[i], kernel_size=1, stride=1, padding=0, bias=False), build_norm_layer(self.norm_cfg, in_channels[i])[1], # we set align_corners=False for HRNet Upsample( scale_factor=2**(j - i), mode='bilinear', align_corners=False))) elif j == i: fuse_layer.append(None) else: conv_downsamples = [] for k in range(i - j): if k == i - j - 1: conv_downsamples.append( nn.Sequential( build_conv_layer( self.conv_cfg, in_channels[j], in_channels[i], kernel_size=3, stride=2, padding=1, bias=False), build_norm_layer(self.norm_cfg, in_channels[i])[1])) else: conv_downsamples.append( nn.Sequential( build_conv_layer( self.conv_cfg, in_channels[j], in_channels[j], kernel_size=3, stride=2, padding=1, bias=False), build_norm_layer(self.norm_cfg, in_channels[j])[1], nn.ReLU(inplace=False))) fuse_layer.append(nn.Sequential(*conv_downsamples)) fuse_layers.append(nn.ModuleList(fuse_layer)) return nn.ModuleList(fuse_layers) def forward(self, x): """Forward function.""" if self.num_branches == 1: return [self.branches[0](x[0])] for i in range(self.num_branches): x[i] = self.branches[i](x[i]) x_fuse = [] for i in range(len(self.fuse_layers)): y = 0 for j in range(self.num_branches): if i == j: y += x[j] elif j > i: y = y + resize( self.fuse_layers[i][j](x[j]), size=x[i].shape[2:], mode='bilinear', align_corners=False) else: y += self.fuse_layers[i][j](x[j]) x_fuse.append(self.relu(y)) return x_fuse @BACKBONES.register_module() class HRNet(nn.Module): """HRNet backbone. High-Resolution Representations for Labeling Pixels and Regions arXiv: https://arxiv.org/abs/1904.04514 Args: extra (dict): detailed configuration for each stage of HRNet. in_channels (int): Number of input image channels. Normally 3. conv_cfg (dict): dictionary to construct and config conv layer. 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. 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. Example: >>> from annotator.mmpkg.mmseg.models import HRNet >>> import torch >>> extra = dict( >>> stage1=dict( >>> num_modules=1, >>> num_branches=1, >>> block='BOTTLENECK', >>> num_blocks=(4, ), >>> num_channels=(64, )), >>> stage2=dict( >>> num_modules=1, >>> num_branches=2, >>> block='BASIC', >>> num_blocks=(4, 4), >>> num_channels=(32, 64)), >>> stage3=dict( >>> num_modules=4, >>> num_branches=3, >>> block='BASIC', >>> num_blocks=(4, 4, 4), >>> num_channels=(32, 64, 128)), >>> stage4=dict( >>> num_modules=3, >>> num_branches=4, >>> block='BASIC', >>> num_blocks=(4, 4, 4, 4), >>> num_channels=(32, 64, 128, 256))) >>> self = HRNet(extra, in_channels=1) >>> self.eval() >>> inputs = torch.rand(1, 1, 32, 32) >>> level_outputs = self.forward(inputs) >>> for level_out in level_outputs: ... print(tuple(level_out.shape)) (1, 32, 8, 8) (1, 64, 4, 4) (1, 128, 2, 2) (1, 256, 1, 1) """ blocks_dict = {'BASIC': BasicBlock, 'BOTTLENECK': Bottleneck} def __init__(self, extra, in_channels=3, conv_cfg=None, norm_cfg=dict(type='BN', requires_grad=True), norm_eval=False, with_cp=False, zero_init_residual=False): super(HRNet, self).__init__() self.extra = extra self.conv_cfg = conv_cfg self.norm_cfg = norm_cfg self.norm_eval = norm_eval self.with_cp = with_cp self.zero_init_residual = zero_init_residual # stem net self.norm1_name, norm1 = build_norm_layer(self.norm_cfg, 64, postfix=1) self.norm2_name, norm2 = build_norm_layer(self.norm_cfg, 64, postfix=2) self.conv1 = build_conv_layer( self.conv_cfg, in_channels, 64, kernel_size=3, stride=2, padding=1, bias=False) self.add_module(self.norm1_name, norm1) self.conv2 = build_conv_layer( self.conv_cfg, 64, 64, kernel_size=3, stride=2, padding=1, bias=False) self.add_module(self.norm2_name, norm2) self.relu = nn.ReLU(inplace=True) # stage 1 self.stage1_cfg = self.extra['stage1'] num_channels = self.stage1_cfg['num_channels'][0] block_type = self.stage1_cfg['block'] num_blocks = self.stage1_cfg['num_blocks'][0] block = self.blocks_dict[block_type] stage1_out_channels = num_channels * block.expansion self.layer1 = self._make_layer(block, 64, num_channels, num_blocks) # stage 2 self.stage2_cfg = self.extra['stage2'] num_channels = self.stage2_cfg['num_channels'] block_type = self.stage2_cfg['block'] block = self.blocks_dict[block_type] num_channels = [channel * block.expansion for channel in num_channels] self.transition1 = self._make_transition_layer([stage1_out_channels], num_channels) self.stage2, pre_stage_channels = self._make_stage( self.stage2_cfg, num_channels) # stage 3 self.stage3_cfg = self.extra['stage3'] num_channels = self.stage3_cfg['num_channels'] block_type = self.stage3_cfg['block'] block = self.blocks_dict[block_type] num_channels = [channel * block.expansion for channel in num_channels] self.transition2 = self._make_transition_layer(pre_stage_channels, num_channels) self.stage3, pre_stage_channels = self._make_stage( self.stage3_cfg, num_channels) # stage 4 self.stage4_cfg = self.extra['stage4'] num_channels = self.stage4_cfg['num_channels'] block_type = self.stage4_cfg['block'] block = self.blocks_dict[block_type] num_channels = [channel * block.expansion for channel in num_channels] self.transition3 = self._make_transition_layer(pre_stage_channels, num_channels) self.stage4, pre_stage_channels = self._make_stage( self.stage4_cfg, num_channels) @property def norm1(self): """nn.Module: the normalization layer named "norm1" """ return getattr(self, self.norm1_name) @property def norm2(self): """nn.Module: the normalization layer named "norm2" """ return getattr(self, self.norm2_name) def _make_transition_layer(self, num_channels_pre_layer, num_channels_cur_layer): """Make transition layer.""" num_branches_cur = len(num_channels_cur_layer) num_branches_pre = len(num_channels_pre_layer) transition_layers = [] for i in range(num_branches_cur): if i < num_branches_pre: if num_channels_cur_layer[i] != num_channels_pre_layer[i]: transition_layers.append( nn.Sequential( build_conv_layer( self.conv_cfg, num_channels_pre_layer[i], num_channels_cur_layer[i], kernel_size=3, stride=1, padding=1, bias=False), build_norm_layer(self.norm_cfg, num_channels_cur_layer[i])[1], nn.ReLU(inplace=True))) else: transition_layers.append(None) else: conv_downsamples = [] for j in range(i + 1 - num_branches_pre): in_channels = num_channels_pre_layer[-1] out_channels = num_channels_cur_layer[i] \ if j == i - num_branches_pre else in_channels conv_downsamples.append( nn.Sequential( build_conv_layer( self.conv_cfg, in_channels, out_channels, kernel_size=3, stride=2, padding=1, bias=False), build_norm_layer(self.norm_cfg, out_channels)[1], nn.ReLU(inplace=True))) transition_layers.append(nn.Sequential(*conv_downsamples)) return nn.ModuleList(transition_layers) def _make_layer(self, block, inplanes, planes, blocks, stride=1): """Make each layer.""" downsample = None if stride != 1 or inplanes != planes * block.expansion: downsample = nn.Sequential( build_conv_layer( self.conv_cfg, inplanes, planes * block.expansion, kernel_size=1, stride=stride, bias=False), build_norm_layer(self.norm_cfg, planes * block.expansion)[1]) layers = [] layers.append( block( inplanes, planes, stride, downsample=downsample, with_cp=self.with_cp, norm_cfg=self.norm_cfg, conv_cfg=self.conv_cfg)) inplanes = planes * block.expansion for i in range(1, blocks): layers.append( block( inplanes, planes, with_cp=self.with_cp, norm_cfg=self.norm_cfg, conv_cfg=self.conv_cfg)) return nn.Sequential(*layers) def _make_stage(self, layer_config, in_channels, multiscale_output=True): """Make each stage.""" num_modules = layer_config['num_modules'] num_branches = layer_config['num_branches'] num_blocks = layer_config['num_blocks'] num_channels = layer_config['num_channels'] block = self.blocks_dict[layer_config['block']] hr_modules = [] for i in range(num_modules): # multi_scale_output is only used for the last module if not multiscale_output and i == num_modules - 1: reset_multiscale_output = False else: reset_multiscale_output = True hr_modules.append( HRModule( num_branches, block, num_blocks, in_channels, num_channels, reset_multiscale_output, with_cp=self.with_cp, norm_cfg=self.norm_cfg, conv_cfg=self.conv_cfg)) return nn.Sequential(*hr_modules), in_channels def init_weights(self, pretrained=None): """Initialize the weights in backbone. Args: pretrained (str, optional): Path to pre-trained weights. Defaults to None. """ if isinstance(pretrained, str): logger = get_root_logger() load_checkpoint(self, pretrained, strict=False, logger=logger) elif pretrained is None: for m in self.modules(): if isinstance(m, nn.Conv2d): kaiming_init(m) elif isinstance(m, (_BatchNorm, nn.GroupNorm)): constant_init(m, 1) if self.zero_init_residual: for m in self.modules(): if isinstance(m, Bottleneck): constant_init(m.norm3, 0) elif isinstance(m, BasicBlock): constant_init(m.norm2, 0) else: raise TypeError('pretrained must be a str or None') def forward(self, x): """Forward function.""" x = self.conv1(x) x = self.norm1(x) x = self.relu(x) x = self.conv2(x) x = self.norm2(x) x = self.relu(x) x = self.layer1(x) x_list = [] for i in range(self.stage2_cfg['num_branches']): if self.transition1[i] is not None: x_list.append(self.transition1[i](x)) else: x_list.append(x) y_list = self.stage2(x_list) x_list = [] for i in range(self.stage3_cfg['num_branches']): if self.transition2[i] is not None: x_list.append(self.transition2[i](y_list[-1])) else: x_list.append(y_list[i]) y_list = self.stage3(x_list) x_list = [] for i in range(self.stage4_cfg['num_branches']): if self.transition3[i] is not None: x_list.append(self.transition3[i](y_list[-1])) else: x_list.append(y_list[i]) y_list = self.stage4(x_list) return y_list def train(self, mode=True): """Convert the model into training mode will keeping the normalization layer freezed.""" super(HRNet, self).train(mode) if mode and self.norm_eval: for m in self.modules(): # trick: eval have effect on BatchNorm only if isinstance(m, _BatchNorm): m.eval()