<Neck> add ECA after P3P4P5

models/common.py

@@ -1121,3 +1121,25 @@ class Classify(nn.Module):
         if isinstance(x, list):
             x = torch.cat(x, 1)
         return self.linear(self.drop(self.pool(self.conv(x)).flatten(1)))
+
+# 以下是我自己添加的
+class ECA(nn.Module):
+    """Efficient Channel Attention"""
+    def __init__(self, channels, k_size=3):
+        super().__init__()
+        self.avg_pool = nn.AdaptiveAvgPool2d(1)
+        self.conv = nn.Conv1d(
+            1, 1, kernel_size=k_size,
+            padding=(k_size - 1) // 2,
+            bias=False
+        )
+        self.sigmoid = nn.Sigmoid()
+
+    def forward(self, x):
+        # x: [B, C, H, W]
+        y = self.avg_pool(x)                  # [B, C, 1, 1]
+        y = y.squeeze(-1).transpose(-1, -2)   # [B, 1, C]
+        y = self.conv(y)                      # [B, 1, C]
+        y = self.sigmoid(y)
+        y = y.transpose(-1, -2).unsqueeze(-1) # [B, C, 1, 1]
+        return x * y