（超详细）4-YOLOV5改进-添加ShuffleAttention注意力机制

1、在yolov5/models下面新建一个SE.py文件，在里面放入下面的代码
在这里插入图片描述

代码如下：

import numpy as np
import torch
from torch import nn
from torch.nn import init
from torch.nn.parameter import Parameterclass ShuffleAttention(nn.Module):def __init__(self, channel=512, reduction=16, G=8):super().__init__()self.G = Gself.channel = channelself.avg_pool = nn.AdaptiveAvgPool2d(1)self.gn = nn.GroupNorm(channel // (2 * G), channel // (2 * G))self.cweight = Parameter(torch.zeros(1, channel // (2 * G), 1, 1))self.cbias = Parameter(torch.ones(1, channel // (2 * G), 1, 1))self.sweight = Parameter(torch.zeros(1, channel // (2 * G), 1, 1))self.sbias = Parameter(torch.ones(1, channel // (2 * G), 1, 1))self.sigmoid = nn.Sigmoid()def init_weights(self):for m in self.modules():if isinstance(m, nn.Conv2d):init.kaiming_normal_(m.weight, mode='fan_out')if m.bias is not None:init.constant_(m.bias, 0)elif isinstance(m, nn.BatchNorm2d):init.constant_(m.weight, 1)init.constant_(m.bias, 0)elif isinstance(m, nn.Linear):init.normal_(m.weight, std=0.001)if m.bias is not None:init.constant_(m.bias, 0)@staticmethoddef channel_shuffle(x, groups):b, c, h, w = x.shapex = x.reshape(b, groups, -1, h, w)x = x.permute(0, 2, 1, 3, 4)# flattenx = x.reshape(b, -1, h, w)return xdef forward(self, x):b, c, h, w = x.size()# group into subfeaturesx = x.view(b * self.G, -1, h, w)  # bs*G,c//G,h,w# channel_splitx_0, x_1 = x.chunk(2, dim=1)  # bs*G,c//(2*G),h,w# channel attentionx_channel = self.avg_pool(x_0)  # bs*G,c//(2*G),1,1x_channel = self.cweight * x_channel + self.cbias  # bs*G,c//(2*G),1,1x_channel = x_0 * self.sigmoid(x_channel)# spatial attentionx_spatial = self.gn(x_1)  # bs*G,c//(2*G),h,wx_spatial = self.sweight * x_spatial + self.sbias  # bs*G,c//(2*G),h,wx_spatial = x_1 * self.sigmoid(x_spatial)  # bs*G,c//(2*G),h,w# concatenate along channel axisout = torch.cat([x_channel, x_spatial], dim=1)  # bs*G,c//G,h,wout = out.contiguous().view(b, -1, h, w)# channel shuffleout = self.channel_shuffle(out, 2)return out