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import torch | |
import torch.nn as nn | |
from basicsr.utils.registry import ARCH_REGISTRY | |
from .arch_util import ResidualBlockNoBN, make_layer | |
class MeanShift(nn.Conv2d): | |
""" Data normalization with mean and std. | |
Args: | |
rgb_range (int): Maximum value of RGB. | |
rgb_mean (list[float]): Mean for RGB channels. | |
rgb_std (list[float]): Std for RGB channels. | |
sign (int): For subtraction, sign is -1, for addition, sign is 1. | |
Default: -1. | |
requires_grad (bool): Whether to update the self.weight and self.bias. | |
Default: True. | |
""" | |
def __init__(self, rgb_range, rgb_mean, rgb_std, sign=-1, requires_grad=True): | |
super(MeanShift, self).__init__(3, 3, kernel_size=1) | |
std = torch.Tensor(rgb_std) | |
self.weight.data = torch.eye(3).view(3, 3, 1, 1) | |
self.weight.data.div_(std.view(3, 1, 1, 1)) | |
self.bias.data = sign * rgb_range * torch.Tensor(rgb_mean) | |
self.bias.data.div_(std) | |
self.requires_grad = requires_grad | |
class EResidualBlockNoBN(nn.Module): | |
"""Enhanced Residual block without BN. | |
There are three convolution layers in residual branch. | |
""" | |
def __init__(self, in_channels, out_channels): | |
super(EResidualBlockNoBN, self).__init__() | |
self.body = nn.Sequential( | |
nn.Conv2d(in_channels, out_channels, 3, 1, 1), | |
nn.ReLU(inplace=True), | |
nn.Conv2d(out_channels, out_channels, 3, 1, 1), | |
nn.ReLU(inplace=True), | |
nn.Conv2d(out_channels, out_channels, 1, 1, 0), | |
) | |
self.relu = nn.ReLU(inplace=True) | |
def forward(self, x): | |
out = self.body(x) | |
out = self.relu(out + x) | |
return out | |
class MergeRun(nn.Module): | |
""" Merge-and-run unit. | |
This unit contains two branches with different dilated convolutions, | |
followed by a convolution to process the concatenated features. | |
Paper: Real Image Denoising with Feature Attention | |
Ref git repo: https://github.com/saeed-anwar/RIDNet | |
""" | |
def __init__(self, in_channels, out_channels, kernel_size=3, stride=1, padding=1): | |
super(MergeRun, self).__init__() | |
self.dilation1 = nn.Sequential( | |
nn.Conv2d(in_channels, out_channels, kernel_size, stride, padding), nn.ReLU(inplace=True), | |
nn.Conv2d(out_channels, out_channels, kernel_size, stride, 2, 2), nn.ReLU(inplace=True)) | |
self.dilation2 = nn.Sequential( | |
nn.Conv2d(in_channels, out_channels, kernel_size, stride, 3, 3), nn.ReLU(inplace=True), | |
nn.Conv2d(out_channels, out_channels, kernel_size, stride, 4, 4), nn.ReLU(inplace=True)) | |
self.aggregation = nn.Sequential( | |
nn.Conv2d(out_channels * 2, out_channels, kernel_size, stride, padding), nn.ReLU(inplace=True)) | |
def forward(self, x): | |
dilation1 = self.dilation1(x) | |
dilation2 = self.dilation2(x) | |
out = torch.cat([dilation1, dilation2], dim=1) | |
out = self.aggregation(out) | |
out = out + x | |
return out | |
class ChannelAttention(nn.Module): | |
"""Channel attention. | |
Args: | |
num_feat (int): Channel number of intermediate features. | |
squeeze_factor (int): Channel squeeze factor. Default: | |
""" | |
def __init__(self, mid_channels, squeeze_factor=16): | |
super(ChannelAttention, self).__init__() | |
self.attention = nn.Sequential( | |
nn.AdaptiveAvgPool2d(1), nn.Conv2d(mid_channels, mid_channels // squeeze_factor, 1, padding=0), | |
nn.ReLU(inplace=True), nn.Conv2d(mid_channels // squeeze_factor, mid_channels, 1, padding=0), nn.Sigmoid()) | |
def forward(self, x): | |
y = self.attention(x) | |
return x * y | |
class EAM(nn.Module): | |
"""Enhancement attention modules (EAM) in RIDNet. | |
This module contains a merge-and-run unit, a residual block, | |
an enhanced residual block and a feature attention unit. | |
Attributes: | |
merge: The merge-and-run unit. | |
block1: The residual block. | |
block2: The enhanced residual block. | |
ca: The feature/channel attention unit. | |
""" | |
def __init__(self, in_channels, mid_channels, out_channels): | |
super(EAM, self).__init__() | |
self.merge = MergeRun(in_channels, mid_channels) | |
self.block1 = ResidualBlockNoBN(mid_channels) | |
self.block2 = EResidualBlockNoBN(mid_channels, out_channels) | |
self.ca = ChannelAttention(out_channels) | |
# The residual block in the paper contains a relu after addition. | |
self.relu = nn.ReLU(inplace=True) | |
def forward(self, x): | |
out = self.merge(x) | |
out = self.relu(self.block1(out)) | |
out = self.block2(out) | |
out = self.ca(out) | |
return out | |
class RIDNet(nn.Module): | |
"""RIDNet: Real Image Denoising with Feature Attention. | |
Ref git repo: https://github.com/saeed-anwar/RIDNet | |
Args: | |
in_channels (int): Channel number of inputs. | |
mid_channels (int): Channel number of EAM modules. | |
Default: 64. | |
out_channels (int): Channel number of outputs. | |
num_block (int): Number of EAM. Default: 4. | |
img_range (float): Image range. Default: 255. | |
rgb_mean (tuple[float]): Image mean in RGB orders. | |
Default: (0.4488, 0.4371, 0.4040), calculated from DIV2K dataset. | |
""" | |
def __init__(self, | |
in_channels, | |
mid_channels, | |
out_channels, | |
num_block=4, | |
img_range=255., | |
rgb_mean=(0.4488, 0.4371, 0.4040), | |
rgb_std=(1.0, 1.0, 1.0)): | |
super(RIDNet, self).__init__() | |
self.sub_mean = MeanShift(img_range, rgb_mean, rgb_std) | |
self.add_mean = MeanShift(img_range, rgb_mean, rgb_std, 1) | |
self.head = nn.Conv2d(in_channels, mid_channels, 3, 1, 1) | |
self.body = make_layer( | |
EAM, num_block, in_channels=mid_channels, mid_channels=mid_channels, out_channels=mid_channels) | |
self.tail = nn.Conv2d(mid_channels, out_channels, 3, 1, 1) | |
self.relu = nn.ReLU(inplace=True) | |
def forward(self, x): | |
res = self.sub_mean(x) | |
res = self.tail(self.body(self.relu(self.head(res)))) | |
res = self.add_mean(res) | |
out = x + res | |
return out | |