import functools import torch import torch.nn as nn import torch.nn.functional as F import models.archs.srflow_orig.module_util as mutil from models.archs.arch_util import default_init_weights, ConvGnSilu from utils.util import opt_get class ResidualDenseBlock(nn.Module): """Residual Dense Block. Used in RRDB block in ESRGAN. Args: mid_channels (int): Channel number of intermediate features. growth_channels (int): Channels for each growth. """ def __init__(self, mid_channels=64, growth_channels=32): super(ResidualDenseBlock, self).__init__() for i in range(5): out_channels = mid_channels if i == 4 else growth_channels self.add_module( f'conv{i+1}', nn.Conv2d(mid_channels + i * growth_channels, out_channels, 3, 1, 1)) self.lrelu = nn.LeakyReLU(negative_slope=0.2, inplace=True) for i in range(5): default_init_weights(getattr(self, f'conv{i+1}'), 0.1) def forward(self, x): """Forward function. Args: x (Tensor): Input tensor with shape (n, c, h, w). Returns: Tensor: Forward results. """ x1 = self.lrelu(self.conv1(x)) x2 = self.lrelu(self.conv2(torch.cat((x, x1), 1))) x3 = self.lrelu(self.conv3(torch.cat((x, x1, x2), 1))) x4 = self.lrelu(self.conv4(torch.cat((x, x1, x2, x3), 1))) x5 = self.conv5(torch.cat((x, x1, x2, x3, x4), 1)) # Emperically, we use 0.2 to scale the residual for better performance return x5 * 0.2 + x class RRDB(nn.Module): """Residual in Residual Dense Block. Used in RRDB-Net in ESRGAN. Args: mid_channels (int): Channel number of intermediate features. growth_channels (int): Channels for each growth. """ def __init__(self, mid_channels, growth_channels=32): super(RRDB, self).__init__() self.rdb1 = ResidualDenseBlock(mid_channels, growth_channels) self.rdb2 = ResidualDenseBlock(mid_channels, growth_channels) self.rdb3 = ResidualDenseBlock(mid_channels, growth_channels) def forward(self, x): """Forward function. Args: x (Tensor): Input tensor with shape (n, c, h, w). Returns: Tensor: Forward results. """ out = self.rdb1(x) out = self.rdb2(out) out = self.rdb3(out) # Emperically, we use 0.2 to scale the residual for better performance return out * 0.2 + x class RRDBWithBypass(nn.Module): """Residual in Residual Dense Block. Used in RRDB-Net in ESRGAN. Args: mid_channels (int): Channel number of intermediate features. growth_channels (int): Channels for each growth. """ def __init__(self, mid_channels, growth_channels=32): super(RRDBWithBypass, self).__init__() self.rdb1 = ResidualDenseBlock(mid_channels, growth_channels) self.rdb2 = ResidualDenseBlock(mid_channels, growth_channels) self.rdb3 = ResidualDenseBlock(mid_channels, growth_channels) self.bypass = nn.Sequential(ConvGnSilu(mid_channels*2, mid_channels, kernel_size=3, bias=True, activation=True, norm=True), ConvGnSilu(mid_channels, mid_channels//2, kernel_size=3, bias=False, activation=True, norm=False), ConvGnSilu(mid_channels//2, 1, kernel_size=3, bias=False, activation=False, norm=False), nn.Sigmoid()) def forward(self, x): """Forward function. Args: x (Tensor): Input tensor with shape (n, c, h, w). Returns: Tensor: Forward results. """ out = self.rdb1(x) out = self.rdb2(out) out = self.rdb3(out) bypass = self.bypass(torch.cat([x, out], dim=1)) self.bypass_map = bypass.detach().clone() # Empirically, we use 0.2 to scale the residual for better performance return out * 0.2 * bypass + x class RRDBNet(nn.Module): def __init__(self, in_nc, out_nc, nf, nb, gc=32, scale=4, opt=None): self.opt = opt super(RRDBNet, self).__init__() bypass = opt_get(self.opt, ['networks', 'generator', 'rrdb_bypass']) if bypass: RRDB_block_f = functools.partial(RRDBWithBypass, mid_channels=nf, growth_channels=gc) else: RRDB_block_f = functools.partial(RRDB, mid_channels=nf, growth_channels=gc) self.scale = scale self.conv_first = nn.Conv2d(in_nc, nf, 3, 1, 1, bias=True) self.body = mutil.make_layer(RRDB_block_f, nb) self.conv_body = nn.Conv2d(nf, nf, 3, 1, 1, bias=True) #### upsampling self.conv_up1 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True) self.conv_up2 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True) if self.scale >= 8: self.conv_up3 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True) if self.scale >= 16: self.conv_up4 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True) if self.scale >= 32: self.conv_up5 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True) self.conv_hr = nn.Conv2d(nf, nf, 3, 1, 1, bias=True) self.conv_last = nn.Conv2d(nf, out_nc, 3, 1, 1, bias=True) self.lrelu = nn.LeakyReLU(negative_slope=0.2, inplace=True) def forward(self, x, get_steps=False): fea = self.conv_first(x) block_idxs = opt_get(self.opt, ['networks', 'generator','flow', 'stackRRDB', 'blocks']) or [] block_results = {} for idx, m in enumerate(self.body.children()): fea = m(fea) for b in block_idxs: if b == idx: block_results["block_{}".format(idx)] = fea trunk = self.conv_body(fea) last_lr_fea = fea + trunk fea_up2 = self.conv_up1(F.interpolate(last_lr_fea, scale_factor=2, mode='nearest')) fea = self.lrelu(fea_up2) fea_up4 = self.conv_up2(F.interpolate(fea, scale_factor=2, mode='nearest')) fea = self.lrelu(fea_up4) fea_up8 = None fea_up16 = None fea_up32 = None if self.scale >= 8: fea_up8 = self.conv_up3(F.interpolate(fea, scale_factor=2, mode='nearest')) fea = self.lrelu(fea_up8) if self.scale >= 16: fea_up16 = self.conv_up4(F.interpolate(fea, scale_factor=2, mode='nearest')) fea = self.lrelu(fea_up16) if self.scale >= 32: fea_up32 = self.conv_up5(F.interpolate(fea, scale_factor=2, mode='nearest')) fea = self.lrelu(fea_up32) out = self.conv_last(self.lrelu(self.conv_hr(fea))) if self.scale >= 4: results = {'last_lr_fea': last_lr_fea, 'fea_up1': last_lr_fea, 'fea_up2': fea_up2, 'fea_up4': fea_up4, 'fea_up8': fea_up8, 'fea_up16': fea_up16, 'fea_up32': fea_up32, 'out': out} fea_up0_en = opt_get(self.opt, ['networks', 'generator','flow', 'fea_up0']) or False if fea_up0_en: results['fea_up0'] = F.interpolate(last_lr_fea, scale_factor=1/2, mode='bilinear', align_corners=False, recompute_scale_factor=True) fea_upn1_en = opt_get(self.opt, ['networks', 'generator','flow', 'fea_up-1']) or False if fea_upn1_en: results['fea_up-1'] = F.interpolate(last_lr_fea, scale_factor=1/4, mode='bilinear', align_corners=False, recompute_scale_factor=True) elif self.scale == 2: # "Pretend" this is is 4x by shuffling around the inputs a bit. half = F.interpolate(last_lr_fea, scale_factor=1/2, mode='bilinear', align_corners=False, recompute_scale_factor=True) quarter = F.interpolate(last_lr_fea, scale_factor=1/4, mode='bilinear', align_corners=False, recompute_scale_factor=True) eighth = F.interpolate(last_lr_fea, scale_factor=1/8, mode='bilinear', align_corners=False, recompute_scale_factor=True) results = {'last_lr_fea': half, 'fea_up1': half, 'fea_up2': last_lr_fea, 'fea_up4': fea_up2, 'fea_up8': fea_up4, 'fea_up16': fea_up8, 'fea_up32': fea_up16, 'out': out} fea_up0_en = opt_get(self.opt, ['networks', 'generator','flow', 'fea_up0']) or False if fea_up0_en: results['fea_up0'] = quarter fea_upn1_en = opt_get(self.opt, ['networks', 'generator','flow', 'fea_up-1']) or False if fea_upn1_en: results['fea_up-1'] = eighth else: raise NotImplementedError if get_steps: for k, v in block_results.items(): results[k] = v return results else: return out