ultralytics 8.0.108 add Meituan YOLOv6 models (#2811)

Co-authored-by: Michael Currie <mcurrie@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Hicham Talaoubrid <98521878+HichTala@users.noreply.github.com>
Co-authored-by: Zlobin Vladimir <vladimir.zlobin@intel.com>
Co-authored-by: Szymon Mikler <sjmikler@gmail.com>

ultralytics/models/v6/yolov6.yaml

@@ -0,0 +1,51 @@
+# Ultralytics YOLO 🚀, AGPL-3.0 license
+# YOLOv6 object detection model with P3-P5 outputs. For Usage examples see https://docs.ultralytics.com/tasks/detect
+
+# Parameters
+act: nn.ReLU()
+nc: 80  # number of classes
+scales: # model compound scaling constants, i.e. 'model=yolov6n.yaml' will call yolov8.yaml with scale 'n'
+  # [depth, width, max_channels]
+  n: [ 0.33, 0.25, 1024 ]
+  s: [ 0.33, 0.50, 1024 ]
+  m: [ 0.67, 0.75, 768 ]
+  l: [ 1.00, 1.00, 512 ]
+  x: [ 1.00, 1.25, 512 ]
+
+# YOLOv6-3.0s backbone
+backbone:
+  # [from, repeats, module, args]
+  - [ -1, 1, Conv, [ 64, 3, 2 ] ]  # 0-P1/2
+  - [ -1, 1, Conv, [ 128, 3, 2 ] ]  # 1-P2/4
+  - [ -1, 6, Conv, [ 128, 3, 1 ] ]
+  - [ -1, 1, Conv, [ 256, 3, 2 ] ]  # 3-P3/8
+  - [ -1, 12, Conv, [ 256, 3, 1 ] ]
+  - [ -1, 1, Conv, [ 512, 3, 2 ] ]  # 5-P4/16
+  - [ -1, 18, Conv, [ 512, 3, 1 ] ]
+  - [ -1, 1, Conv, [ 1024, 3, 2 ] ]  # 7-P5/32
+  - [ -1, 9, Conv, [ 1024, 3, 1 ] ]
+  - [ -1, 1, SPPF, [ 1024, 5 ] ]  # 9
+
+# YOLOv6-3.0s head
+head:
+  - [ -1, 1, nn.ConvTranspose2d, [ 256, 2, 2, 0 ] ]
+  - [ [ -1, 6 ], 1, Concat, [ 1 ] ]  # cat backbone P4
+  - [ -1, 1, Conv, [ 256, 3, 1 ] ]
+  - [ -1, 9, Conv, [ 256, 3, 1 ] ]  # 13
+
+  - [ -1, 1, nn.ConvTranspose2d, [ 128, 2, 2, 0 ] ]
+  - [ [ -1, 4 ], 1, Concat, [ 1 ] ]  # cat backbone P3
+  - [ -1, 1, Conv, [ 128, 3, 1 ] ]
+  - [ -1, 9, Conv, [ 128, 3, 1 ] ]  # 17
+
+  - [ -1, 1, Conv, [ 128, 3, 2 ] ]
+  - [ [ -1, 12 ], 1, Concat, [ 1 ] ]  # cat head P4
+  - [ -1, 1, Conv, [ 256, 3, 1 ] ]
+  - [ -1, 9, Conv, [ 256, 3, 1 ] ]  # 21
+
+  - [ -1, 1, Conv, [ 256, 3, 2 ] ]
+  - [ [ -1, 9 ], 1, Concat, [ 1 ] ]  # cat head P5
+  - [ -1, 1, Conv, [ 512, 3, 1 ] ]
+  - [ -1, 9, Conv, [ 512, 3, 1 ] ]  # 25
+
+  - [ [ 17, 21, 25 ], 1, Detect, [ nc ] ]  # Detect(P3, P4, P5)