import torch.nn as nn
import torch.nn.functional as F
import torch
[docs]class AttentionUNet(torch.nn.Module):
"""
UNet, down sampling & up sampling for global reasoning
"""
def __init__(self, input_channels, class_number, **kwargs):
super(AttentionUNet, self).__init__()
down_channel = kwargs['down_channel'] # default = 256
down_channel_2 = down_channel * 2
up_channel_1 = down_channel_2 * 2
up_channel_2 = down_channel * 2
self.inc = InConv(input_channels, down_channel)
self.down1 = DownLayer(down_channel, down_channel_2)
self.down2 = DownLayer(down_channel_2, down_channel_2)
self.up1 = UpLayer(up_channel_1, up_channel_1 // 4)
self.up2 = UpLayer(up_channel_2, up_channel_2 // 4)
self.outc = OutConv(up_channel_2 // 4, class_number)
[docs] def forward(self, attention_channels):
"""
Given multi-channel attention map, return the logits of every one mapping into 3-class
:param attention_channels:
:return:
"""
# attention_channels as the shape of: batch_size x channel x width x height
x = attention_channels
x1 = self.inc(x)
x2 = self.down1(x1)
x3 = self.down2(x2)
x = self.up1(x3, x2)
x = self.up2(x, x1)
output = self.outc(x)
# attn_map as the shape of: batch_size x width x height x class
output = output.permute(0, 2, 3, 1).contiguous()
return output
[docs]class DoubleConv(nn.Module):
"""(conv => [BN] => ReLU) * 2"""
def __init__(self, in_ch, out_ch):
super(DoubleConv, self).__init__()
self.double_conv = nn.Sequential(nn.Conv2d(in_ch, out_ch, kernel_size=3, padding=1),
nn.BatchNorm2d(out_ch),
nn.ReLU(inplace=True),
nn.Conv2d(out_ch, out_ch, kernel_size=3, padding=1),
nn.BatchNorm2d(out_ch),
nn.ReLU(inplace=True))
[docs] def forward(self, x):
x = self.double_conv(x)
return x
[docs]class InConv(nn.Module):
def __init__(self, in_ch, out_ch):
super(InConv, self).__init__()
self.conv = DoubleConv(in_ch, out_ch)
[docs] def forward(self, x):
x = self.conv(x)
return x
[docs]class DownLayer(nn.Module):
def __init__(self, in_ch, out_ch):
super(DownLayer, self).__init__()
self.maxpool_conv = nn.Sequential(
nn.MaxPool2d(kernel_size=2),
DoubleConv(in_ch, out_ch)
)
[docs] def forward(self, x):
x = self.maxpool_conv(x)
return x
[docs]class UpLayer(nn.Module):
def __init__(self, in_ch, out_ch, bilinear=True):
super(UpLayer, self).__init__()
if bilinear:
self.up = nn.Upsample(scale_factor=2, mode='bilinear',
align_corners=True)
else:
self.up = nn.ConvTranspose2d(in_ch // 2, in_ch // 2, 2, stride=2)
self.conv = DoubleConv(in_ch, out_ch)
[docs] def forward(self, x1, x2):
x1 = self.up(x1)
diffY = x2.size()[2] - x1.size()[2]
diffX = x2.size()[3] - x1.size()[3]
x1 = F.pad(x1, (diffX // 2, diffX - diffX // 2, diffY // 2, diffY -
diffY // 2))
x = torch.cat([x2, x1], dim=1)
x = self.conv(x)
return x
[docs]class OutConv(nn.Module):
def __init__(self, in_ch, out_ch):
super(OutConv, self).__init__()
self.conv = nn.Conv2d(in_ch, out_ch, 1)
[docs] def forward(self, x):
x = self.conv(x)
return x