fix yolov5s.yaml

models/yolov5s.yaml

@@ -48,25 +48,27 @@ backbone:
 #     [[17, 20, 23], 1, Detect, [nc, anchors]], # Detect(P3, P4, P5)
 #   ]
 
-head:
-  # Top-down
-  [-1, 1, Conv, [512, 1, 1]]
-  [-1, 1, nn.Upsample, [None, 2, "nearest"]]
-  [[-1, 6], 1, WeightedAdd, [2]]
-  [-1, 3, C3, [512, False]]
+# YOLOv5 v6.0 head (PAN + WeightedAdd)
+head: [
+  # ---------- Top-down FPN ----------
+  [-1, 1, Conv, [512, 1, 1]],                     # 10: reduce P5
+  [-1, 1, nn.Upsample, [None, 2, "nearest"]],     # 11
+  [[-1, 6], 1, WeightedAdd, [2]],                 # 12: P5 + backbone P4
+  [-1, 3, C3, [512, False]],                      # 13
 
-  [-1, 1, Conv, [256, 1, 1]]
-  [-1, 1, nn.Upsample, [None, 2, "nearest"]]
-  [[-1, 4], 1, WeightedAdd, [2]]
-  [-1, 3, C3, [256, False]]
+  [-1, 1, Conv, [256, 1, 1]],                     # 14: reduce
+  [-1, 1, nn.Upsample, [None, 2, "nearest"]],     # 15
+  [[-1, 4], 1, WeightedAdd, [2]],                 # 16: P4 + backbone P3
+  [-1, 3, C3, [256, False]],                      # 17 (P3/8)
 
-  # Bottom-up
-  [-1, 1, Conv, [256, 3, 2]]
-  [[-1, 14], 1, WeightedAdd, [2]]
-  [-1, 3, C3, [512, False]]
+  # ---------- Bottom-up PAN ----------
+  [-1, 1, Conv, [256, 3, 2]],                     # 18: downsample
+  [[-1, 13], 1, WeightedAdd, [2]],                # 19: P3 -> P4
+  [-1, 3, C3, [512, False]],                      # 20 (P4/16)
 
-  [-1, 1, Conv, [512, 3, 2]]
-  [[-1, 10], 1, WeightedAdd, [2]]
-  [-1, 3, C3, [1024, False]]
+  [-1, 1, Conv, [512, 3, 2]],                     # 21: downsample
+  [[-1, 10], 1, WeightedAdd, [2]],                # 22: P4 -> P5
+  [-1, 3, C3, [1024, False]],                     # 23 (P5/32)
 
-  [[17, 20, 23], 1, Detect, [nc, anchors]]
+  [[17, 20, 23], 1, Detect, [nc, anchors]],       # Detect(P3, P4, P5)
+]