Upload densenet_withglam.py

densenet_withglam.py

@@ -0,0 +1,82 @@
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+
+class GLAM(nn.Module):
+    """
+    Global-Local Attention Module (GLAM) that produces a refined feature map.
+    """
+    def __init__(self, in_channels, reduction_ratio=8):
+        super(GLAM, self).__init__()
+        
+        # --- Local Channel Attention ---
+        self.local_channel_conv = nn.Conv2d(in_channels, in_channels // reduction_ratio, kernel_size=1)
+        self.local_channel_act = nn.Sigmoid()
+        self.local_channel_expand = nn.Conv2d(in_channels // reduction_ratio, in_channels, kernel_size=1)
+        
+        # --- Local Spatial Attention ---
+        # 3-dilated, 5-dilated conv merges
+        self.local_spatial_conv3 = nn.Conv2d(in_channels, in_channels, kernel_size=3, padding=3, dilation=3)
+        self.local_spatial_conv5 = nn.Conv2d(in_channels, in_channels, kernel_size=3, padding=5, dilation=5)
+        self.local_spatial_merge = nn.Conv2d(in_channels * 3, in_channels, kernel_size=1)
+        self.local_spatial_act = nn.Sigmoid()
+        
+        # --- Global Channel Attention ---
+        self.global_avg_pool = nn.AdaptiveAvgPool2d(1)
+        self.global_channel_fc1 = nn.Linear(in_channels, in_channels // reduction_ratio)
+        self.global_channel_fc2 = nn.Linear(in_channels // reduction_ratio, in_channels)
+        self.global_channel_act = nn.Sigmoid()
+        
+        # --- Global Spatial Attention ---
+        self.global_spatial_conv = nn.Conv2d(in_channels, 1, kernel_size=1)
+        self.global_spatial_softmax = nn.Softmax(dim=-1)
+        
+        
+        # --- Weighted paramerers initialization ---
+        self.local_attention_weight = nn.Parameter(torch.tensor(1.0))  
+        self.global_attention_weight = nn.Parameter(torch.tensor(1.0))
+        
+
+    def forward(self, x):
+        # Local Channel Attention
+        lca = self.local_channel_conv(x)       
+        lca = self.local_channel_act(lca)      
+        lca = self.local_channel_expand(lca)   
+        lca_out = lca * x                      
+
+        # Local Spatial Attention
+        lsa3 = self.local_spatial_conv3(x)
+        lsa5 = self.local_spatial_conv5(x)
+        lsa_cat = torch.cat([x, lsa3, lsa5], dim=1)
+        lsa = self.local_spatial_merge(lsa_cat)
+        lsa = self.local_spatial_act(lsa)
+        lsa_out = lsa * lca_out
+        lsa_out = lsa_out + lca_out
+
+        # Global Channel Attention
+        B, C, H, W = x.size()
+        gca = self.global_avg_pool(x).view(B, C)  
+        gca = F.relu(self.global_channel_fc1(gca), inplace=True)
+        gca = self.global_channel_fc2(gca)
+        gca = self.global_channel_act(gca)
+        gca = gca.view(B, C, 1, 1)
+        gca_out = gca * x
+
+        # Global Spatial Attention
+        gsa = self.global_spatial_conv(x)  # [B, 1, H, W]
+        gsa = gsa.view(B, -1)              # [B, H*W]
+        gsa = self.global_spatial_softmax(gsa)
+        gsa = gsa.view(B, 1, H, W)
+        gsa_out = gsa * gca_out
+        gsa_out = gsa_out + gca_out
+
+        # Fuse
+        out =  lsa_out*self.local_attention_weight +  gsa_out*self.global_attention_weight + x
+        return out
+def get_model_with_attention(model_name, num_classes):
+    if model_name == 'densenet169':
+        model = models.densenet169(pretrained=True)
+        in_channels = model.classifier.in_features
+        model.features = nn.Sequential(model.features, nn.ReLU(inplace=True), GLAM(in_channels))
+        model.classifier = nn.Linear(in_channels, num_classes)