YOLOv8改进 | 2023 | DiverseBranchBlock多元分支模块（有效涨点）

一、本文介绍

本文带来的改进机制是YOLOv8模型与多元分支模块（Diverse Branch Block）的结合，Diverse Branch Block (DBB) 是一种用于增强卷积神经网络性能的结构重新参数化技术。这种技术的核心在于结合多样化的分支，这些分支具有不同的尺度和复杂度，从而丰富特征空间。我将其放在了YOLOv8的不同位置上均有一定的涨点幅度，同时这个DBB模块的参数量并不会上涨太多，我添加三个该机制到模型中，GFLOPs上涨了0.4。

推荐指数：⭐⭐⭐⭐

打星原因：为什么打四颗星是因为我觉得这个机制的计算量会上涨，这是扣分点，其次涨幅效果也比较一般但是有涨点，当然可能是数据集的原因毕竟不同的数据集效果不同

专栏回顾：YOLOv8改进系列专栏——本专栏持续复习各种顶会内容——科研必备

训练结果对比图->

这次试验我用的数据集大概有七八百张照片训练了150个epochs，虽然没有完全拟合但是效果有一定的涨点幅度，所以大家可以进行尝试毕竟不同的数据集上效果也可能差很多，同时我在后面给了多种yaml文件大家可以分别进行实验来检验效果。

一、本文介绍

二、Diverse Branch Block原理

2.1 Diverse Branch Block的基本原理

2.2 多样化分支结构

2.3 训练与推理分离

2.4 宏观架构不变

三、Diverse Branch Block的完整代码

3.1 Diverse Branch Block的核心代码

3.2 修改了Diverse Branch Block的C2f和Bottleneck(使用这个否则大家自己修改可能报错)

四、手把手教你添加Diverse Branch Block机制

4.1 Diverse Branch Block的添加教程

4.2 Diverse Branch Block的yaml文件和训练截图

4.2.1 Diverse Branch Block的yaml版本一(推荐)

4.2.2 Diverse Branch Block的yaml版本二

4.2.3Diverse Branch Block的yaml版本三

4.2.2 Diverse Branch Block的训练过程截图

五、Diverse Branch Block可添加的位置

5.1 推荐Diverse Branch Block可添加的位置

六、本文总结

二、Diverse Branch Block原理

论文地址：论文官方地址

代码地址：官方代码地址

2.1 Diverse Branch Block的基本原理

Diverse Branch Block（DBB）的基本原理是在训练阶段增加卷积层的复杂性，通过引入不同尺寸和结构的卷积分支来丰富网络的特征表示能力。我们可以将基本原理可以概括为以下几点：

1. 多样化分支结构：DBB 结合了不同尺度和复杂度的分支，如不同大小的卷积核和平均池化，以增加单个卷积的特征表达能力。
2. 训练与推理分离：在训练阶段，DBB 采用复杂的分支结构，而在推理阶段，这些分支可以被等效地转换为单个卷积层，以保持高效推理。
3. 宏观架构不变：DBB 允许在不改变整体网络架构的情况下，作为常规卷积层的替代品插入到现有网络中。

下面我将为大家展示Diverse Branch Block（DBB）的设计示例：

在训练时（左侧），DBB由不同大小的卷积层和平均池化层组成，这些层以一种复杂的方式并行排列，并最终合并输出。训练完成后，这些复杂的结构会转换成单个卷积层，用于模型的推理阶段（右侧），以此保持推理时的效率。这种转换允许DBB在保持宏观架构不变的同时，增加训练时的微观结构复杂性。

2.2 多样化分支结构

多样化分支结构是在卷积神经网络中引入的一种结构，旨在通过多样化的分支来增强模型的特征提取能力。这些分支包含不同尺寸的卷积层和池化层，以及其他潜在的操作，它们并行工作以捕获不同的特征表示。在训练完成后，这些复杂的结构可以合并并简化为单个的卷积层，以便在推理时不增加额外的计算负担。这种设计使得DBB可以作为现有卷积层的直接替换，增强了现有网络架构的性能，而不需要修改整体架构。

下面我详细展示了如何通过六种转换方法将训练时的Diverse Branch Block（DBB）转换为推理时的常规卷积层，每一种转换对应于一种特定的操作：

1. Transform I：将具有批量规范化（batch norm）的卷积层融合。
2. Transform II：合并具有相同配置的卷积层的输出。
3. Transform III：合并序列卷积层。
4. Transform IV：通过深度串联（concat）来合并卷积层。
5. Transform V：将平均池化（AVG）操作融入卷积操作中。
6. Transform VI：结合不同尺度的卷积层。

可以看到右侧的框显示了经过这些转换后，可以实现的推理时DBB，其中包含了常规卷积、平均池化和批量规范化操作。这些转换确保了在不增加推理时负担的同时，能够在训练时利用DBB的多样化特征提取能力。

2.3 训练与推理分离

训练与推理分离的概念是指在模型训练阶段使用复杂的DBB结构，而在模型推理阶段则转换为简化的卷积结构。这种设计允许模型在训练时利用DBB的多样性来增强特征提取和学习能力，而在实际应用中，即推理时，通过减少计算量来保持高效。这样，模型在保持高性能的同时，也保证了运行速度和资源效率。

上面我将展示在训练阶段如何通过不同的卷积组合（如图中的1x1和KxK卷积），以及在推理阶段如何将这些组合转换成一个简化的结构（如图中的转换IV所示的拼接操作）：

经过分析，我们可以发现它说明了三种不同的情况：

A）组卷积（Groupwise conv）：将输入分成多个组，每个组使用不同的卷积核。
B）训练时的1x1-KxK结构：首先应用1x1的卷积（减少特征维度），然后是分组的KxK卷积。
C）从转换IV的角度看：这是将多个分组的卷积输出合并的视角。这里，组内卷积后的特征图先分别通过1x1卷积处理，然后再进行拼接（concat）。

2.4 宏观架构不变

宏观架构不变指的是DBB在设计时考虑到了与现有的网络架构兼容性，确保可以在不改变整体网络架构（如ResNet等流行架构）的前提下，将DBB作为一个模块嵌入。这意味着DBB增强了网络的特征提取能力，同时保持了原有网络结构的布局，确保了推理时的效率和性能。这样的设计允许研究者和开发者将DBB直接应用到现有的深度学习模型中，而无需进行大规模的架构调整。

三、Diverse Branch Block的完整代码

3.1 Diverse Branch Block的核心代码

Diverse Branch Block的本体代码，我们可以将其在'ultralytics/nn/modules'文件下面建立一个py文件复制粘贴进去，然后具体使用的方法可以看章节四。

import torch
import torch.nn as nn
import torch.nn.functional as F
import numpy as np
from .conv import Conv, autopad

def transI_fusebn(kernel, bn):
    gamma = bn.weight
    std = (bn.running_var + bn.eps).sqrt()
    return kernel * ((gamma / std).reshape(-1, 1, 1, 1)), bn.bias - bn.running_mean * gamma / std


def transII_addbranch(kernels, biases):
    return sum(kernels), sum(biases)


def transIII_1x1_kxk(k1, b1, k2, b2, groups):
    if groups == 1:
        k = F.conv2d(k2, k1.permute(1, 0, 2, 3))  #
        b_hat = (k2 * b1.reshape(1, -1, 1, 1)).sum((1, 2, 3))
    else:
        k_slices = []
        b_slices = []
        k1_T = k1.permute(1, 0, 2, 3)
        k1_group_width = k1.size(0) // groups
        k2_group_width = k2.size(0) // groups
        for g in range(groups):
            k1_T_slice = k1_T[:, g * k1_group_width:(g + 1) * k1_group_width, :, :]
            k2_slice = k2[g * k2_group_width:(g + 1) * k2_group_width, :, :, :]
            k_slices.append(F.conv2d(k2_slice, k1_T_slice))
            b_slices.append(
                (k2_slice * b1[g * k1_group_width:(g + 1) * k1_group_width].reshape(1, -1, 1, 1)).sum((1, 2, 3)))
        k, b_hat = transIV_depthconcat(k_slices, b_slices)
    return k, b_hat + b2


def transIV_depthconcat(kernels, biases):
    return torch.cat(kernels, dim=0), torch.cat(biases)


def transV_avg(channels, kernel_size, groups):
    input_dim = channels // groups
    k = torch.zeros((channels, input_dim, kernel_size, kernel_size))
    k[np.arange(channels), np.tile(np.arange(input_dim), groups), :, :] = 1.0 / kernel_size ** 2
    return k


#   This has not been tested with non-square kernels (kernel.size(2) != kernel.size(3)) nor even-size kernels
def transVI_multiscale(kernel, target_kernel_size):
    H_pixels_to_pad = (target_kernel_size - kernel.size(2)) // 2
    W_pixels_to_pad = (target_kernel_size - kernel.size(3)) // 2
    return F.pad(kernel, [H_pixels_to_pad, H_pixels_to_pad, W_pixels_to_pad, W_pixels_to_pad])


def conv_bn(in_channels, out_channels, kernel_size, stride=1, padding=0, dilation=1, groups=1,
            padding_mode='zeros'):
    conv_layer = nn.Conv2d(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size,
                           stride=stride, padding=padding, dilation=dilation, groups=groups,
                           bias=False, padding_mode=padding_mode)
    bn_layer = nn.BatchNorm2d(num_features=out_channels, affine=True)
    se = nn.Sequential()
    se.add_module('conv', conv_layer)
    se.add_module('bn', bn_layer)
    return se


class IdentityBasedConv1x1(nn.Conv2d):
    def __init__(self, channels, groups=1):
        super(IdentityBasedConv1x1, self).__init__(in_channels=channels, out_channels=channels, kernel_size=1, stride=1,
                                                   padding=0, groups=groups, bias=False)

        assert channels % groups == 0
        input_dim = channels // groups
        id_value = np.zeros((channels, input_dim, 1, 1))
        for i in range(channels):
            id_value[i, i % input_dim, 0, 0] = 1
        self.id_tensor = torch.from_numpy(id_value).type_as(self.weight)
        nn.init.zeros_(self.weight)

    def forward(self, input):
        kernel = self.weight + self.id_tensor.to(self.weight.device).type_as(self.weight)
        result = F.conv2d(input, kernel, None, stride=1, padding=0, dilation=self.dilation, groups=self.groups)
        return result

    def get_actual_kernel(self):
        return self.weight + self.id_tensor.to(self.weight.device)


class BNAndPadLayer(nn.Module):
    def __init__(self,
                 pad_pixels,
                 num_features,
                 eps=1e-5,
                 momentum=0.1,
                 affine=True,
                 track_running_stats=True):
        super(BNAndPadLayer, self).__init__()
        self.bn = nn.BatchNorm2d(num_features, eps, momentum, affine, track_running_stats)
        self.pad_pixels = pad_pixels

    def forward(self, input):
        output = self.bn(input)
        if self.pad_pixels > 0:
            if self.bn.affine:
                pad_values = self.bn.bias.detach() - self.bn.running_mean * self.bn.weight.detach() / torch.sqrt(
                    self.bn.running_var + self.bn.eps)
            else:
                pad_values = - self.bn.running_mean / torch.sqrt(self.bn.running_var + self.bn.eps)
            output = F.pad(output, [self.pad_pixels] * 4)
            pad_values = pad_values.view(1, -1, 1, 1)
            output[:, :, 0:self.pad_pixels, :] = pad_values
            output[:, :, -self.pad_pixels:, :] = pad_values
            output[:, :, :, 0:self.pad_pixels] = pad_values
            output[:, :, :, -self.pad_pixels:] = pad_values
        return output

    @property
    def weight(self):
        return self.bn.weight

    @property
    def bias(self):
        return self.bn.bias

    @property
    def running_mean(self):
        return self.bn.running_mean

    @property
    def running_var(self):
        return self.bn.running_var

    @property
    def eps(self):
        return self.bn.eps


class DiverseBranchBlock(nn.Module):
    def __init__(self, in_channels, out_channels, kernel_size,
                 stride=1, padding=None, dilation=1, groups=1,
                 internal_channels_1x1_3x3=None,
                 deploy=False, single_init=False):
        super(DiverseBranchBlock, self).__init__()
        self.deploy = deploy

        self.nonlinear = Conv.default_act

        self.kernel_size = kernel_size
        self.out_channels = out_channels
        self.groups = groups

        if padding is None:
            padding = autopad(kernel_size, padding, dilation)
        assert padding == kernel_size // 2

        if deploy:
            self.dbb_reparam = nn.Conv2d(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size,
                                         stride=stride,
                                         padding=padding, dilation=dilation, groups=groups, bias=True)

        else:

            self.dbb_origin = conv_bn(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size,
                                      stride=stride, padding=padding, dilation=dilation, groups=groups)

            self.dbb_avg = nn.Sequential()
            if groups < out_channels:
                self.dbb_avg.add_module('conv',
                                        nn.Conv2d(in_channels=in_channels, out_channels=out_channels, kernel_size=1,
                                                  stride=1, padding=0, groups=groups, bias=False))
                self.dbb_avg.add_module('bn', BNAndPadLayer(pad_pixels=padding, num_features=out_channels))
                self.dbb_avg.add_module('avg', nn.AvgPool2d(kernel_size=kernel_size, stride=stride, padding=0))
                self.dbb_1x1 = conv_bn(in_channels=in_channels, out_channels=out_channels, kernel_size=1, stride=stride,
                                       padding=0, groups=groups)
            else:
                self.dbb_avg.add_module('avg', nn.AvgPool2d(kernel_size=kernel_size, stride=stride, padding=padding))

            self.dbb_avg.add_module('avgbn', nn.BatchNorm2d(out_channels))

            if internal_channels_1x1_3x3 is None:
                internal_channels_1x1_3x3 = in_channels if groups < out_channels else 2 * in_channels  # For mobilenet, it is better to have 2X internal channels

            self.dbb_1x1_kxk = nn.Sequential()
            if internal_channels_1x1_3x3 == in_channels:
                self.dbb_1x1_kxk.add_module('idconv1', IdentityBasedConv1x1(channels=in_channels, groups=groups))
            else:
                self.dbb_1x1_kxk.add_module('conv1',
                                            nn.Conv2d(in_channels=in_channels, out_channels=internal_channels_1x1_3x3,
                                                      kernel_size=1, stride=1, padding=0, groups=groups, bias=False))
            self.dbb_1x1_kxk.add_module('bn1', BNAndPadLayer(pad_pixels=padding, num_features=internal_channels_1x1_3x3,
                                                             affine=True))
            self.dbb_1x1_kxk.add_module('conv2',
                                        nn.Conv2d(in_channels=internal_channels_1x1_3x3, out_channels=out_channels,
                                                  kernel_size=kernel_size, stride=stride, padding=0, groups=groups,
                                                  bias=False))
            self.dbb_1x1_kxk.add_module('bn2', nn.BatchNorm2d(out_channels))

        #   The experiments reported in the paper used the default initialization of bn.weight (all as 1). But changing the initialization may be useful in some cases.
        if single_init:
            #   Initialize the bn.weight of dbb_origin as 1 and others as 0. This is not the default setting.
            self.single_init()

    def get_equivalent_kernel_bias(self):
        k_origin, b_origin = transI_fusebn(self.dbb_origin.conv.weight, self.dbb_origin.bn)

        if hasattr(self, 'dbb_1x1'):
            k_1x1, b_1x1 = transI_fusebn(self.dbb_1x1.conv.weight, self.dbb_1x1.bn)
            k_1x1 = transVI_multiscale(k_1x1, self.kernel_size)
        else:
            k_1x1, b_1x1 = 0, 0

        if hasattr(self.dbb_1x1_kxk, 'idconv1'):
            k_1x1_kxk_first = self.dbb_1x1_kxk.idconv1.get_actual_kernel()
        else:
            k_1x1_kxk_first = self.dbb_1x1_kxk.conv1.weight
        k_1x1_kxk_first, b_1x1_kxk_first = transI_fusebn(k_1x1_kxk_first, self.dbb_1x1_kxk.bn1)
        k_1x1_kxk_second, b_1x1_kxk_second = transI_fusebn(self.dbb_1x1_kxk.conv2.weight, self.dbb_1x1_kxk.bn2)
        k_1x1_kxk_merged, b_1x1_kxk_merged = transIII_1x1_kxk(k_1x1_kxk_first, b_1x1_kxk_first, k_1x1_kxk_second,
                                                              b_1x1_kxk_second, groups=self.groups)

        k_avg = transV_avg(self.out_channels, self.kernel_size, self.groups)
        k_1x1_avg_second, b_1x1_avg_second = transI_fusebn(k_avg.to(self.dbb_avg.avgbn.weight.device),
                                                           self.dbb_avg.avgbn)
        if hasattr(self.dbb_avg, 'conv'):
            k_1x1_avg_first, b_1x1_avg_first = transI_fusebn(self.dbb_avg.conv.weight, self.dbb_avg.bn)
            k_1x1_avg_merged, b_1x1_avg_merged = transIII_1x1_kxk(k_1x1_avg_first, b_1x1_avg_first, k_1x1_avg_second,
                                                                  b_1x1_avg_second, groups=self.groups)
        else:
            k_1x1_avg_merged, b_1x1_avg_merged = k_1x1_avg_second, b_1x1_avg_second

        return transII_addbranch((k_origin, k_1x1, k_1x1_kxk_merged, k_1x1_avg_merged),
                                 (b_origin, b_1x1, b_1x1_kxk_merged, b_1x1_avg_merged))

    def switch_to_deploy(self):
        if hasattr(self, 'dbb_reparam'):
            return
        kernel, bias = self.get_equivalent_kernel_bias()
        self.dbb_reparam = nn.Conv2d(in_channels=self.dbb_origin.conv.in_channels,
                                     out_channels=self.dbb_origin.conv.out_channels,
                                     kernel_size=self.dbb_origin.conv.kernel_size, stride=self.dbb_origin.conv.stride,
                                     padding=self.dbb_origin.conv.padding, dilation=self.dbb_origin.conv.dilation,
                                     groups=self.dbb_origin.conv.groups, bias=True)
        self.dbb_reparam.weight.data = kernel
        self.dbb_reparam.bias.data = bias
        for para in self.parameters():
            para.detach_()
        self.__delattr__('dbb_origin')
        self.__delattr__('dbb_avg')
        if hasattr(self, 'dbb_1x1'):
            self.__delattr__('dbb_1x1')
        self.__delattr__('dbb_1x1_kxk')

    def forward(self, inputs):
        if hasattr(self, 'dbb_reparam'):
            return self.nonlinear(self.dbb_reparam(inputs))

        out = self.dbb_origin(inputs)
        if hasattr(self, 'dbb_1x1'):
            out += self.dbb_1x1(inputs)
        out += self.dbb_avg(inputs)
        out += self.dbb_1x1_kxk(inputs)
        return self.nonlinear(out)

    def init_gamma(self, gamma_value):
        if hasattr(self, "dbb_origin"):
            torch.nn.init.constant_(self.dbb_origin.bn.weight, gamma_value)
        if hasattr(self, "dbb_1x1"):
            torch.nn.init.constant_(self.dbb_1x1.bn.weight, gamma_value)
        if hasattr(self, "dbb_avg"):
            torch.nn.init.constant_(self.dbb_avg.avgbn.weight, gamma_value)
        if hasattr(self, "dbb_1x1_kxk"):
            torch.nn.init.constant_(self.dbb_1x1_kxk.bn2.weight, gamma_value)

    def single_init(self):
        self.init_gamma(0.0)
        if hasattr(self, "dbb_origin"):
            torch.nn.init.constant_(self.dbb_origin.bn.weight, 1.0)

3.2 修改了Diverse Branch Block的C2f和Bottleneck(使用这个否则大家自己修改可能报错)

class Bottleneck_DBB(nn.Module):
    """Standard bottleneck."""

    def __init__(self, c1, c2, shortcut=True, g=1, k=(3, 3), e=0.5):
        """Initializes a bottleneck module with given input/output channels, shortcut option, group, kernels, and
        expansion.
        """
        super().__init__()
        c_ = int(c2 * e)  # hidden channels
        self.cv1 = Conv(c1, c_, k[0], 1)
        self.cv2 = DiverseBranchBlock(c_, c2, k[1], 1, g)
        self.add = shortcut and c1 == c2

    def forward(self, x):
        """'forward()' applies the YOLO FPN to input data."""
        return x + self.cv2(self.cv1(x)) if self.add else self.cv2(self.cv1(x))


class C2f_DBB(nn.Module):
    """Faster Implementation of CSP Bottleneck with 2 convolutions."""
    def __init__(self, c1, c2, n=1, shortcut=False, g=1, e=0.5):
        """Initialize CSP bottleneck layer with two convolutions with arguments ch_in, ch_out, number, shortcut, groups,
        expansion.
        """
        super().__init__()
        self.c = int(c2 * e)  # hidden channels
        self.cv1 = Conv(c1, 2 * self.c, 1, 1)
        self.cv2 = Conv((2 + n) * self.c, c2, 1)  # optional act=FReLU(c2)
        self.m = nn.ModuleList(Bottleneck_DBB(self.c, self.c, shortcut, g, k=(3, 3), e=1.0) for _ in range(n))

    def forward(self, x):
        """Forward pass through C2f layer."""
        x = self.cv1(x)
        x = x.chunk(2, 1)
        y = list(x)
        # y = list(self.cv1(x).chunk(2, 1))
        y.extend(m(y[-1]) for m in self.m)
        return self.cv2(torch.cat(y, 1))

    def forward_split(self, x):
        """Forward pass using split() instead of chunk()."""
        y = list(self.cv1(x).split((self.c, self.c), 1))
        y.extend(m(y[-1]) for m in self.m)
        return self.cv2(torch.cat(y, 1))

四、手把手教你添加Diverse Branch Block机制

4.1 Diverse Branch Block的添加教程

添加教程这里不再重复介绍、因为专栏内容有许多，添加过程又需要截特别图片会导致文章大家读者也不通顺如果你已经会添加注意力机制了，可以跳过本章节，如果你还不会，大家可以看我下面的文章，里面详细的介绍了拿到一个任意机制(C2f、Conv、Bottleneck、Loss、DetectHead)如何添加到你的网络结构中去。

这里需要注意的是我上面提供了两段代码一个是C2f-DBB一个是Diverse Branch Block的本体代码，这两种方法的添加方式有些不同。

最后强调一下Diverse Branch Block是一种可以替换卷积的模块，所以我们直接将其按照卷积的方式添加即可！！！

C2f-DBB按照正常C2f的机制进行添加即可！！！

添加教程->YOLOv8改进 | 如何在网络结构中添加注意力机制、C2f、卷积、Neck、检测头

4.2 Diverse Branch Block的yaml文件和训练截图

下面推荐几个版本的yaml文件给大家，大家可以复制进行训练，但是组合用很多具体那种最有效果都不一定，针对不同的数据集效果也不一样，我不可每一种都做实验，所以我下面推荐了三种我自己认为可能有效果的配合方式，你也可以自己进行组合。

4.2.1 Diverse Branch Block的yaml版本一(推荐)

下面的配置文件为我修改的C2f-DBB的位置(我的对比实验是用这个版本跑出来的)。

# Ultralytics YOLO 🚀, AGPL-3.0 license
# YOLOv8 object detection model with P3-P5 outputs. For Usage examples see https://docs.ultralytics.com/tasks/detect

# Parameters
nc: 80  # number of classes
scales: # model compound scaling constants, i.e. 'model=yolov8n.yaml' will call yolov8.yaml with scale 'n'
  # [depth, width, max_channels]
  n: [0.33, 0.25, 1024]  # YOLOv8n summary: 225 layers,  3157200 parameters,  3157184 gradients,   8.9 GFLOPs
  s: [0.33, 0.50, 1024]  # YOLOv8s summary: 225 layers, 11166560 parameters, 11166544 gradients,  28.8 GFLOPs
  m: [0.67, 0.75, 768]   # YOLOv8m summary: 295 layers, 25902640 parameters, 25902624 gradients,  79.3 GFLOPs
  l: [1.00, 1.00, 512]   # YOLOv8l summary: 365 layers, 43691520 parameters, 43691504 gradients, 165.7 GFLOPs
  x: [1.00, 1.25, 512]   # YOLOv8x summary: 365 layers, 68229648 parameters, 68229632 gradients, 258.5 GFLOPs

# YOLOv8.0n 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, 3, C2f, [128, True]]
  - [-1, 1, Conv, [256, 3, 2]]  # 3-P3/8
  - [-1, 6, C2f, [256, True]]
  - [-1, 1, Conv, [512, 3, 2]]  # 5-P4/16
  - [-1, 6, C2f, [512, True]]
  - [-1, 1, Conv, [1024, 3, 2]]  # 7-P5/32
  - [-1, 3, C2f, [1024, True]]
  - [-1, 1, SPPF, [1024, 5]]  # 9

# YOLOv8.0n head
head:
  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 6], 1, Concat, [1]]  # cat backbone P4
  - [-1, 3, C2f, [512]]  # 12

  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 4], 1, Concat, [1]]  # cat backbone P3
  - [-1, 3, C2f_DBB, [256]]  # 15 (P3/8-small)

  - [-1, 1, Conv, [256, 3, 2]]
  - [[-1, 12], 1, Concat, [1]]  # cat head P4
  - [-1, 3, C2f_DBB, [512]]  # 18 (P4/16-medium)

  - [-1, 1, Conv, [512, 3, 2]]
  - [[-1, 9], 1, Concat, [1]]  # cat head P5
  - [-1, 3, C2f_DBB, [1024]]  # 21 (P5/32-large)

  - [[15, 18, 21], 1, Detect, [nc]]  # Detect(P3, P4, P5)

4.2.2 Diverse Branch Block的yaml版本二

添加的版本二具体那种适合你需要大家自己多做实验来尝试。

# Ultralytics YOLO 🚀, AGPL-3.0 license
# YOLOv8 object detection model with P3-P5 outputs. For Usage examples see https://docs.ultralytics.com/tasks/detect

# Parameters
nc: 80  # number of classes
scales: # model compound scaling constants, i.e. 'model=yolov8n.yaml' will call yolov8.yaml with scale 'n'
  # [depth, width, max_channels]
  n: [0.33, 0.25, 1024]  # YOLOv8n summary: 225 layers,  3157200 parameters,  3157184 gradients,   8.9 GFLOPs
  s: [0.33, 0.50, 1024]  # YOLOv8s summary: 225 layers, 11166560 parameters, 11166544 gradients,  28.8 GFLOPs
  m: [0.67, 0.75, 768]   # YOLOv8m summary: 295 layers, 25902640 parameters, 25902624 gradients,  79.3 GFLOPs
  l: [1.00, 1.00, 512]   # YOLOv8l summary: 365 layers, 43691520 parameters, 43691504 gradients, 165.7 GFLOPs
  x: [1.00, 1.25, 512]   # YOLOv8x summary: 365 layers, 68229648 parameters, 68229632 gradients, 258.5 GFLOPs

# YOLOv8.0n 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, 3, C2f, [128, True]]
  - [-1, 1, Conv, [256, 3, 2]]  # 3-P3/8
  - [-1, 6, C2f, [256, True]]
  - [-1, 1, Conv, [512, 3, 2]]  # 5-P4/16
  - [-1, 6, C2f, [512, True]]
  - [-1, 1, Conv, [1024, 3, 2]]  # 7-P5/32
  - [-1, 3, C2f, [1024, True]]
  - [-1, 1, SPPF, [1024, 5]]  # 9

# YOLOv8.0n head
head:
  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 6], 1, Concat, [1]]  # cat backbone P4
  - [-1, 3, C2f, [512]]  # 12

  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 4], 1, Concat, [1]]  # cat backbone P3
  - [-1, 3, C2f_DBB, [256]]  # 15 (P3/8-small)

  - [-1, 1, DiverseBranchBlock, [256, 3, 2]]
  - [[-1, 12], 1, Concat, [1]]  # cat head P4
  - [-1, 3, C2f_DBB, [512]]  # 18 (P4/16-medium)

  - [-1, 1, DiverseBranchBlock, [512, 3, 2]]
  - [[-1, 9], 1, Concat, [1]]  # cat head P5
  - [-1, 3, C2f_DBB, [1024]]  # 21 (P5/32-large)

  - [[15, 18, 21], 1, Detect, [nc]]  # Detect(P3, P4, P5)

4.2.3Diverse Branch Block的yaml版本三

# Ultralytics YOLO 🚀, AGPL-3.0 license
# YOLOv8 object detection model with P3-P5 outputs. For Usage examples see https://docs.ultralytics.com/tasks/detect

# Parameters
nc: 80  # number of classes
scales: # model compound scaling constants, i.e. 'model=yolov8n.yaml' will call yolov8.yaml with scale 'n'
  # [depth, width, max_channels]
  n: [0.33, 0.25, 1024]  # YOLOv8n summary: 225 layers,  3157200 parameters,  3157184 gradients,   8.9 GFLOPs
  s: [0.33, 0.50, 1024]  # YOLOv8s summary: 225 layers, 11166560 parameters, 11166544 gradients,  28.8 GFLOPs
  m: [0.67, 0.75, 768]   # YOLOv8m summary: 295 layers, 25902640 parameters, 25902624 gradients,  79.3 GFLOPs
  l: [1.00, 1.00, 512]   # YOLOv8l summary: 365 layers, 43691520 parameters, 43691504 gradients, 165.7 GFLOPs
  x: [1.00, 1.25, 512]   # YOLOv8x summary: 365 layers, 68229648 parameters, 68229632 gradients, 258.5 GFLOPs

# YOLOv8.0n backbone
backbone:
  # [from, repeats, module, args]
  - [-1, 1, Conv, [64, 3, 2]]  # 0-P1/2
  - [-1, 1, DiverseBranchBlock, [128, 3, 2]]  # 1-P2/4
  - [-1, 3, C2f, [128, True]]
  - [-1, 1, DiverseBranchBlock, [256, 3, 2]]  # 3-P3/8
  - [-1, 6, C2f, [256, True]]
  - [-1, 1, DiverseBranchBlock, [512, 3, 2]]  # 5-P4/16
  - [-1, 6, C2f, [512, True]]
  - [-1, 1, DiverseBranchBlock, [1024, 3, 2]]  # 7-P5/32
  - [-1, 3, C2f, [1024, True]]
  - [-1, 1, SPPF, [1024, 5]]  # 9

# YOLOv8.0n head
head:
  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 6], 1, Concat, [1]]  # cat backbone P4
  - [-1, 3, C2f, [512]]  # 12

  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 4], 1, Concat, [1]]  # cat backbone P3
  - [-1, 3, C2f, [256]]  # 15 (P3/8-small)

  - [-1, 1, Conv, [256, 3, 2]]
  - [[-1, 12], 1, Concat, [1]]  # cat head P4
  - [-1, 3, C2f, [512]]  # 18 (P4/16-medium)

  - [-1, 1, Conv, [512, 3, 2]]
  - [[-1, 9], 1, Concat, [1]]  # cat head P5
  - [-1, 3, C2f, [1024]]  # 21 (P5/32-large)

  - [[15, 18, 21], 1, Detect, [nc]]  # Detect(P3, P4, P5)

4.2.2 Diverse Branch Block的训练过程截图

下面是添加了Diverse Branch Block的训练截图。

(最近有人说我改的代码是没有发全的，我不知道这群人是怎么说出这种话的，希望大家如果用我的代码成功的可以在评论区支持一下，我也好发更多的改进毕竟免费给大家看。同时有问题皆可在评论区留言我看到都会回复)

大家可以看下面的运行结果和添加的未知所以不存在我发的代码不全或者运行不了的问题大家有问题也可以在评论区评论我看到都会为大家解答(我知道的)。

五、Diverse Branch Block可添加的位置

5.1 推荐Diverse Branch Block可添加的位置

Diverse Branch Block是一种即插即用的可替换卷积的模块，其可以添加的位置有很多，添加的位置不同效果也不同，所以我下面推荐几个添加的位，置大家可以进行参考，当然不一定要按照我推荐的地方添加。

残差连接中：在残差网络的残差连接中加入Diverse Branch Block(yaml文件一)。

Neck部分：YOLOv8的Neck部分负责特征融合，这里添加修改后的C2f_DBB可以帮助模型更有效地融合不同层次的特征(yaml文件二)。

Backbone：可以替换中干网络中的卷积部分(yaml文件三)

六、本文总结

到此本文的正式分享内容就结束了，在这里给大家推荐我的YOLOv8改进有效涨点专栏，本专栏目前为新开的平均质量分98分，后期我会根据各种最新的前沿顶会进行论文复现，也会对一些老的改进机制进行补充，目前本专栏免费阅读(暂时，大家尽早关注不迷路~)，如果大家觉得本文帮助到你了，订阅本专栏，关注后续更多的更新~