文章目录
前言
在之前的这篇博客中,简要介绍了BiFPN的原理,以及YOLOv5作者如何结合BiFPN:【魔改YOLOv5-6.x(中)】:加入ACON激活函数、CBAM和CA注意力机制、加权双向特征金字塔BiFPN
本文将尝试进一步结合BiFPN,主要参考自:YOLOv5结合BiFPN
修改common.py
- 复制粘贴一下代码:
# 结合BiFPN 设置可学习参数 学习不同分支的权重classBiFPN_Concat(nn.Module):def__init__(self, c1, c2):super(BiFPN_Concat, self).__init__()# 设置可学习参数 nn.Parameter的作用是:将一个不可训练的类型Tensor转换成可以训练的类型parameter# 并且会向宿主模型注册该参数 成为其一部分 即model.parameters()会包含这个parameter# 从而在参数优化的时候可以自动一起优化
self.w1 = nn.Parameter(torch.ones(2, dtype=torch.float32), requires_grad=True)
self.w2 = nn.Parameter(torch.ones(3, dtype=torch.float32), requires_grad=True)
self.epsilon =0.0001
self.conv = nn.Conv2d(c1, c2, kernel_size=1, stride=1, padding=0)
self.silu = nn.SiLU()defforward(self, x):iflen(x)==2:# add两个分支
w = self.w1
weight = w /(torch.sum(w, dim=0)+ self.epsilon)return self.conv(self.silu(weight[0]* x[0]+ weight[1]* x[1]))eliflen(x)==3:# add三个分支
w = self.w2
weight = w /(torch.sum(w, dim=0)+ self.epsilon)# 将权重进行归一化# Fast normalized fusionreturn self.conv(self.silu(weight[0]* x[0]+ weight[1]* x[1]+ weight[2]* x[2]))
修改yolo.py
- 在
parse_model
函数中找到elif m is Concat:
语句,在其后面加上BiFPN_Concat
相关语句:
elif m is Concat:
c2 =sum(ch[x]for x in f)elif m is BiFPN_Concat:# 增加BiFPN_Concat
c2 =max([ch[x]for x in f])
yolov5s-bifpn.yaml
修改模型配置文件时要注意以下几点:
- 这里的yaml文件只修改了一处,也就是将19层的Concat换成了BiFPN_Concat,要想修改其他层的Concat,可以类比进行修改
- BiFPN_Concat本质是add操作,不是concat操作,因此,BiFPN_Concat的各个输入层要求大小完全一致(通道数、feature map大小等),因此,这里要修改之前的参数[-1, 13, 6],来满足这个要求: - -1层就是上一层的输出,原来上一层的输出channel数为256,这里改成512- 13层就是这里
[-1, 3, C3, [512, False]], # 13
- 这样修改后,BiFPN_Concat各个输入大小都是[bs,256,40,40]
- 最后BiFPN_Concat后面的参数层设置为[256, 256]
也就是输入输出channel数都是256
# YOLOv5 🚀 by Ultralytics, GPL-3.0 license# Parameters
nc:80# number of classes
depth_multiple:0.33# model depth multiple
width_multiple:0.50# layer channel multiple
anchors:-[10,13,16,30,33,23]# P3/8-[30,61,62,45,59,119]# P4/16-[116,90,156,198,373,326]# P5/32# YOLOv5 v6.0 backbone
backbone:# [from, number, module, args][[-1,1, Conv,[64,6,2,2]],# 0-P1/2[-1,1, Conv,[128,3,2]],# 1-P2/4[-1,3, C3,[128]],[-1,1, Conv,[256,3,2]],# 3-P3/8[-1,6, C3,[256]],[-1,1, Conv,[512,3,2]],# 5-P4/16[-1,9, C3,[512]],[-1,1, Conv,[1024,3,2]],# 7-P5/32[-1,3, C3,[1024]],[-1,1, SPPF,[1024,5]],# 9]# YOLOv5 v6.0 BiFPN head
head:[[-1,1, Conv,[512,1,1]],[-1,1, nn.Upsample,[None,2,'nearest']],[[-1,6],1, Concat,[1]],# cat backbone P4[-1,3, C3,[512,False]],# 13[-1,1, Conv,[256,1,1]],[-1,1, nn.Upsample,[None,2,'nearest']],[[-1,4],1, Concat,[1]],# cat backbone P3[-1,3, C3,[256,False]],# 17 (P3/8-small)[-1,1, Conv,[512,3,2]],# 为了BiFPN正确add,调整channel数[[-1,13,6],1, BiFPN_Concat,[256,256]],# cat P4 <--- BiFPN change 注意v5s通道数是默认参数的一半[-1,3, C3,[512,False]],# 20 (P4/16-medium)[-1,1, Conv,[512,3,2]],[[-1,10],1, Concat,[1]],# cat head P5[-1,3, C3,[1024,False]],# 23 (P5/32-large)[[17,20,23],1, Detect,[nc, anchors]],# Detect(P3, P4, P5)]
测试结果
最后可以参考这篇博客:【YOLOv5-6.x】模型参数及detect层输出测试(自用),进行模型配置文件测试并查看输出结果:
from n params module arguments
0-113520 models.common.Conv [3,32,6,2,2]1-1118560 models.common.Conv [32,64,3,2]2-1118816 models.common.C3 [64,64,1]3-1173984 models.common.Conv [64,128,3,2]4-12115712 models.common.C3 [128,128,2]5-11295424 models.common.Conv [128,256,3,2]6-13625152 models.common.C3 [256,256,3]7-111180672 models.common.Conv [256,512,3,2]8-111182720 models.common.C3 [512,512,1]9-11656896 models.common.SPPF [512,512,5]10-11131584 models.common.Conv [512,256,1,1]11-110 torch.nn.modules.upsampling.Upsample [None,2,'nearest']12[-1,6]10 models.common.Concat [1]13-11361984 models.common.C3 [512,256,1,False]14-1133024 models.common.Conv [256,128,1,1]15-110 torch.nn.modules.upsampling.Upsample [None,2,'nearest']16[-1,4]10 models.common.Concat [1]17-1190880 models.common.C3 [256,128,1,False]18-11295424 models.common.Conv [128,256,3,2]19[-1,13,6]165797 models.common.BiFPN_Concat [256,256]20-11296448 models.common.C3 [256,256,1,False]21-11590336 models.common.Conv [256,256,3,2]22[-1,10]10 models.common.Concat [1]23-111182720 models.common.C3 [512,512,1,False]24[17,20,23]1229245 models.yolo.Detect [80,[[10,13,16,30,33,23],[30,61,62,45,59,119],[116,90,156,198,373,326]],[128,256,512]]
Model Summary:272 layers,7448898 parameters,7448898 gradients,17.2 GFLOPs
Concat全部换成BiFPN_Concat
# YOLOv5 🚀 by Ultralytics, GPL-3.0 license# Parameters
nc:80# number of classes
depth_multiple:0.33# model depth multiple
width_multiple:0.50# layer channel multiple
anchors:-[10,13,16,30,33,23]# P3/8-[30,61,62,45,59,119]# P4/16-[116,90,156,198,373,326]# P5/32# YOLOv5 v6.0 backbone
backbone:# [from, number, module, args][[-1,1, Conv,[64,6,2,2]],# 0-P1/2[-1,1, Conv,[128,3,2]],# 1-P2/4[-1,3, C3,[128]],[-1,1, Conv,[256,3,2]],# 3-P3/8[-1,6, C3,[256]],[-1,1, Conv,[512,3,2]],# 5-P4/16[-1,9, C3,[512]],[-1,1, Conv,[1024,3,2]],# 7-P5/32[-1,3, C3,[1024]],[-1,1, SPPF,[1024,5]],# 9]# YOLOv5 v6.0 BiFPN head
head:[[-1,1, Conv,[512,1,1]],[-1,1, nn.Upsample,[None,2,'nearest']],[[-1,6],1, BiFPN_Concat,[256,256]],# cat backbone P4[-1,3, C3,[512,False]],# 13[-1,1, Conv,[256,1,1]],[-1,1, nn.Upsample,[None,2,'nearest']],[[-1,4],1, BiFPN_Concat,[128,128]],# cat backbone P3[-1,3, C3,[256,False]],# 17 (P3/8-small)[-1,1, Conv,[512,3,2]],# 为了BiFPN正确add,调整channel数[[-1,13,6],1, BiFPN_Concat,[256,256]],# cat P4 <--- BiFPN change 注意v5s通道数是默认参数的一半[-1,3, C3,[512,False]],# 20 (P4/16-medium)[-1,1, Conv,[512,3,2]],[[-1,10],1, BiFPN_Concat,[256,256]],# cat head P5[-1,3, C3,[1024,False]],# 23 (P5/32-large)[[17,20,23],1, Detect,[nc, anchors]],# Detect(P3, P4, P5)]
模型输出结果:
from n params module arguments
0-113520 models.common.Conv [3,32,6,2,2]1-1118560 models.common.Conv [32,64,3,2]2-1118816 models.common.C3 [64,64,1]3-1173984 models.common.Conv [64,128,3,2]4-12115712 models.common.C3 [128,128,2]5-11295424 models.common.Conv [128,256,3,2]6-13625152 models.common.C3 [256,256,3]7-111180672 models.common.Conv [256,512,3,2]8-111182720 models.common.C3 [512,512,1]9-11656896 models.common.SPPF [512,512,5]10-11131584 models.common.Conv [512,256,1,1]11-110 torch.nn.modules.upsampling.Upsample [None,2,'nearest']12[-1,6]165797 models.common.BiFPN_Concat [256,256]13-11296448 models.common.C3 [256,256,1,False]14-1133024 models.common.Conv [256,128,1,1]15-110 torch.nn.modules.upsampling.Upsample [None,2,'nearest']16[-1,4]116517 models.common.BiFPN_Concat [128,128]17-1174496 models.common.C3 [128,128,1,False]18-11295424 models.common.Conv [128,256,3,2]19[-1,13,6]165797 models.common.BiFPN_Concat [256,256]20-11296448 models.common.C3 [256,256,1,False]21-11590336 models.common.Conv [256,256,3,2]22[-1,10]165797 models.common.BiFPN_Concat [256,256]23-111051648 models.common.C3 [256,512,1,False]24[17,20,23]1229245 models.yolo.Detect [80,[[10,13,16,30,33,23],[30,61,62,45,59,119],[116,90,156,198,373,326]],[128,256,512]]
Model Summary:278 layers,7384017 parameters,7384017 gradients,17.2 GFLOPs
References
YOLOv5结合BiFPN
【论文笔记】EfficientDet(BiFPN)(2020)
nn.Module、nn.Sequential和torch.nn.parameter学习笔记
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