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import torch | |
import torch.nn as nn | |
import torch.nn.functional as F | |
import numpy as np | |
class AttentionGate(nn.Module): | |
def __init__(self, F_g, F_l, F_int): | |
super(AttentionGate, self).__init__() | |
self.W_g = nn.Sequential( | |
nn.Conv2d(F_g, F_int, kernel_size=1, stride=1, padding=0, bias=True), | |
nn.BatchNorm2d(F_int), | |
) | |
self.W_x = nn.Sequential( | |
nn.Conv2d(F_l, F_int, kernel_size=1, stride=1, padding=0, bias=True), | |
nn.BatchNorm2d(F_int), | |
) | |
self.psi = nn.Sequential( | |
nn.Conv2d(F_int, 1, kernel_size=1, stride=1, padding=0, bias=True), | |
nn.BatchNorm2d(1), | |
nn.Sigmoid(), | |
) | |
self.relu = nn.ReLU(inplace=True) | |
def forward(self, g, x): | |
g1 = self.W_g(g) | |
x1 = self.W_x(x) | |
psi = self.relu(g1 + x1) | |
psi = self.psi(psi) | |
return x * psi | |
class DoubleConv(nn.Module): | |
def __init__(self, in_channels, out_channels): | |
super(DoubleConv, self).__init__() | |
self.conv = nn.Sequential( | |
nn.Conv2d(in_channels, out_channels, kernel_size=3, padding=1, bias=False), | |
nn.BatchNorm2d(out_channels), | |
nn.ReLU(inplace=True), | |
nn.Conv2d(out_channels, out_channels, kernel_size=3, padding=1, bias=False), | |
nn.BatchNorm2d(out_channels), | |
nn.ReLU(inplace=True), | |
) | |
def forward(self, x): | |
return self.conv(x) | |
class AttentionUNet(nn.Module): | |
def __init__(self, in_channels=3, out_channels=1, features=[64, 128, 256, 512]): | |
super(AttentionUNet, self).__init__() | |
self.ups = nn.ModuleList() | |
self.downs = nn.ModuleList() | |
self.pool = nn.MaxPool2d(kernel_size=2, stride=2) | |
self.attention_gates = nn.ModuleList() | |
# Down part of U-Net | |
for feature in features: | |
self.downs.append(DoubleConv(in_channels, feature)) | |
in_channels = feature | |
# Up part of U-Net | |
for feature in reversed(features): | |
self.ups.append( | |
nn.ConvTranspose2d( | |
feature * 2, | |
feature, | |
kernel_size=2, | |
stride=2, | |
) | |
) | |
# Attention Gate | |
self.attention_gates.append( | |
AttentionGate(F_g=feature, F_l=feature, F_int=feature // 2) | |
) | |
self.ups.append(DoubleConv(feature * 2, feature)) | |
# Bottleneck | |
self.bottleneck = DoubleConv(features[-1], features[-1] * 2) | |
# Final Conv | |
self.final_conv = nn.Conv2d(features[0], out_channels, kernel_size=1) | |
def forward(self, x): | |
skip_connections = [] | |
# Encoder path | |
for down in self.downs: | |
x = down(x) | |
skip_connections.append(x) | |
x = self.pool(x) | |
x = self.bottleneck(x) | |
skip_connections = skip_connections[::-1] # Reverse to use from back | |
# Decoder path | |
for idx in range(0, len(self.ups), 2): | |
x = self.ups[idx](x) | |
skip_connection = skip_connections[idx // 2] | |
# If sizes don't match | |
if x.shape != skip_connection.shape: | |
x = F.interpolate(x, size=skip_connection.shape[2:]) | |
# Apply attention gate | |
skip_connection = self.attention_gates[idx // 2](g=x, x=skip_connection) | |
# Concatenate | |
concat_skip = torch.cat((skip_connection, x), dim=1) | |
x = self.ups[idx + 1](concat_skip) | |
# Final conv | |
return self.final_conv(x) | |
def load_model(model_path): | |
""" | |
Load the trained model | |
Args: | |
model_path: Path to the model weights | |
Returns: | |
Loaded model | |
""" | |
# Define device | |
device = torch.device("cuda" if torch.cuda.is_available() else "cpu") | |
# Initialize model | |
model = AttentionUNet(in_channels=3, out_channels=1) | |
# Load model weights | |
model.load_state_dict(torch.load(model_path, map_location=device)) | |
# Set model to evaluation mode | |
model.eval() | |
return model.to(device) | |