【YOLOv8改进系列】：
YOLOv8改进系列（1）----替换主干网络之EfficientViT(CVPR2023)
YOLOv8改进系列（2）----替换主干网络之FasterNet
YOLOv8改进系列（3）----替换主干网络之ConvNeXt V2
YOLOv8改进系列（4）----替换C2f之FasterNet中的FasterBlock替换C2f中的Bottleneck
YOLOv8改进系列（5）----替换主干网络之EfficientFormerV2
YOLOv8改进系列（6）----替换主干网络之VanillaNet
YOLOv8改进系列（7）----替换主干网络之LSKNet
YOLOv8改进系列（8）----替换主干网络之Swin Transformer
YOLOv8改进系列（9）----替换主干网络之RepViT
YOLOv8改进系列（10）----替换主干网络之UniRepLKNet
目录
1. Universal Inverted Bottleneck (UIB)
💯一、MobileNetV4介绍
- 论文题目：《MobileNetV4: Universal Models for the Mobile Ecosystem》
- 论文地址：https://arxiv.org/pdf/2404.10518
1. 简介
文章介绍了MobileNetV4（MNv4），这是Google团队开发的最新一代MobileNets，专为移动设备设计的高效神经网络架构。MNv4通过引入通用倒置瓶颈（Universal Inverted Bottleneck，UIB）搜索块、Mobile MQA注意力块以及优化的神经架构搜索（NAS）配方，实现了在多种移动硬件（包括CPU、DSP、GPU和专用加速器）上的高效性能。MNv4模型在保持高性能的同时，显著提高了计算效率，适用于多种移动设备。
2. MobileNetV4 架构设计
背景知识
移动设备上的神经网络需要在准确性和效率之间取得平衡。由于移动设备的计算能力有限，因此需要设计出既高效又能实现实时交互体验的神经网络。MNv4旨在通过创新的架构设计和优化技术，实现这一目标。
研究方法
1. Universal Inverted Bottleneck (UIB)
UIB是MNv4的核心构建块，它将倒置瓶颈（IB）、ConvNext、前馈网络（FFN）和一种新的Extra Depthwise（ExtraDW）变体合并到一个统一的、灵活的结构中。UIB通过可选的深度卷积提供了空间和通道混合的灵活性，扩展了感受野，并提高了计算效率。
2. Mobile MQA
Mobile MQA是一种为移动加速器优化的注意力块，与多头注意力（MHSA）相比，它在移动加速器上实现了超过39%的推理加速。Mobile MQA通过减少内存带宽需求，提高了操作强度，从而在高计算硬件上实现了更高的性能。
3. 优化的NAS配方
MNv4采用了两阶段的NAS方法，首先进行粗粒度搜索以确定最优的滤波器大小，然后进行细粒度搜索以优化UIB的深度卷积层配置。这种方法显著提高了搜索效率，并允许创建比以往更大、更高效的模型。
3. 实验与结果
性能分析
MNv4模型在多种硬件平台上进行了广泛的性能测试，包括ARM Cortex CPU、Qualcomm Hexagon DSP、ARM Mali GPU、Apple Neural Engine和Google EdgeTPU。测试结果显示，MNv4模型在这些平台上都实现了接近Pareto最优的性能，即在不同的硬件上都能在准确性和延迟之间取得良好的平衡。
ImageNet分类任务
在ImageNet-1K分类任务中，MNv4模型与其他领先的高效模型进行了比较。MNv4-Conv-S模型在Pixel 6 CPU上实现了73.8%的Top-1准确率，延迟为2.4ms；而MNv4-Hybrid-L模型在Pixel 8 EdgeTPU上实现了83.4%的Top-1准确率，延迟为3.8ms。通过引入一种新的蒸馏技术，MNv4-Hybrid-L模型的准确率进一步提高到87%，仅比其教师模型低0.5%，但MACs减少了39倍。
COCO目标检测任务
MNv4模型还被用于COCO目标检测任务，与SOTA模型进行了比较。MNv4-Conv-M检测器实现了32.6%的AP，与MobileNetMultiAvg和MobileNetV2相当，但在Pixel 6 CPU上的延迟降低了12%到23%。MNv4-Hybrid-M检测器在AP上提高了1.6%，但延迟增加了18%。
4. 关键结论
MNv4通过UIB和Mobile MQA等创新构建块，以及优化的NAS配方，实现了在多种移动硬件上的高效性能。这些模型不仅在准确性上取得了显著提升，而且在延迟上也表现出色，适用于多种移动应用场景。此外，MNv4还引入了一种新的蒸馏技术，进一步提高了模型的准确率，使其在ImageNet-1K分类任务中达到了87%的Top-1准确率，同时保持了较低的延迟。这些成果为移动设备上的计算机视觉任务提供了新的基准。以下是这篇论文的创新与贡献：
UIB和Mobile MQA：这两个新构建块为MNv4提供了灵活性和效率，使其能够适应不同的硬件平台。
优化的NAS配方：两阶段的NAS方法提高了搜索效率，允许创建更大的模型。
蒸馏技术：通过混合不同增强的数据集和添加平衡的同类数据，提高了模型的泛化能力和准确性。
性能统一性：MNv4是首个在多种硬件平台上实现接近Pareto最优性能的模型，为移动设备上的深度学习模型设计提供了新的方向。
💯二、具体添加方法
第①步：创建MobileNetV4.py
创建完成后，将下面代码直接复制粘贴进去：
from typing import Any, Callable, Dict, List, Mapping, Optional, Tuple, Union
import torch
import torch.nn as nn
__all__ = ['MobileNetV4ConvSmall', 'MobileNetV4ConvMedium', 'MobileNetV4ConvLarge', 'MobileNetV4HybridMedium', 'MobileNetV4HybridLarge']
MNV4ConvSmall_BLOCK_SPECS = {
"conv0": {
"block_name": "convbn",
"num_blocks": 1,
"block_specs": [
[3, 32, 3, 2]
]
},
"layer1": {
"block_name": "convbn",
"num_blocks": 2,
"block_specs": [
[32, 32, 3, 2],
[32, 32, 1, 1]
]
},
"layer2": {
"block_name": "convbn",
"num_blocks": 2,
"block_specs": [
[32, 96, 3, 2],
[96, 64, 1, 1]
]
},
"layer3": {
"block_name": "uib",
"num_blocks": 6,
"block_specs": [
[64, 96, 5, 5, True, 2, 3],
[96, 96, 0, 3, True, 1, 2],
[96, 96, 0, 3, True, 1, 2],
[96, 96, 0, 3, True, 1, 2],
[96, 96, 0, 3, True, 1, 2],
[96, 96, 3, 0, True, 1, 4],
]
},
"layer4": {
"block_name": "uib",
"num_blocks": 6,
"block_specs": [
[96, 128, 3, 3, True, 2, 6],
[128, 128, 5, 5, True, 1, 4],
[128, 128, 0, 5, True, 1, 4],
[128, 128, 0, 5, True, 1, 3],
[128, 128, 0, 3, True, 1, 4],
[128, 128, 0, 3, True, 1, 4],
]
},
"layer5": {
"block_name": "convbn",
"num_blocks": 2,
"block_specs": [
[128, 960, 1, 1],
[960, 1280, 1, 1]
]
}
}
MNV4ConvMedium_BLOCK_SPECS = {
"conv0": {
"block_name": "convbn",
"num_blocks": 1,
"block_specs": [
[3, 32, 3, 2]
]
},
"layer1": {
"block_name": "fused_ib",
"num_blocks": 1,
"block_specs": [
[32, 48, 2, 4.0, True]
]
},
"layer2": {
"block_name": "uib",
"num_blocks": 2,
"block_specs": [
[48, 80, 3, 5, True, 2, 4],
[80, 80, 3, 3, True, 1, 2]
]
},
"layer3": {
"block_name": "uib",
"num_blocks": 8,
"block_specs": [
[80, 160, 3, 5, True, 2, 6],
[160, 160, 3, 3, True, 1, 4],
[160, 160, 3, 3, True, 1, 4],
[160, 160, 3, 5, True, 1, 4],
[160, 160, 3, 3, True, 1, 4],
[160, 160, 3, 0, True, 1, 4],
[160, 160, 0, 0, True, 1, 2],
[160, 160, 3, 0, True, 1, 4]
]
},
"layer4": {
"block_name": "uib",
"num_blocks": 11,
"block_specs": [
[160, 256, 5, 5, True, 2, 6],
[256, 256, 5, 5, True, 1, 4],
[256, 256, 3, 5, True, 1, 4],
[256, 256, 3, 5, True, 1, 4],
[256, 256, 0, 0, True, 1, 4],
[256, 256, 3, 0, True, 1, 4],
[256, 256, 3, 5, True, 1, 2],
[256, 256, 5, 5, True, 1, 4],
[256, 256, 0, 0, True, 1, 4],
[256, 256, 0, 0, True, 1, 4],
[256, 256, 5, 0, True, 1, 2]
]
},
"layer5": {
"block_name": "convbn",
"num_blocks": 2,
"block_specs": [
[256, 960, 1, 1],
[960, 1280, 1, 1]
]
}
}
MNV4ConvLarge_BLOCK_SPECS = {
"conv0": {
"block_name": "convbn",
"num_blocks": 1,
"block_specs": [
[3, 24, 3, 2]
]
},
"layer1": {
"block_name": "fused_ib",
"num_blocks": 1,
"block_specs": [
[24, 48, 2, 4.0, True]
]
},
"layer2": {
"block_name": "uib",
"num_blocks": 2,
"block_specs": [
[48, 96, 3, 5, True, 2, 4],
[96, 96, 3, 3, True, 1, 4]
]
},
"layer3": {
"block_name": "uib",
"num_blocks": 11,
"block_specs": [
[96, 192, 3, 5, True, 2, 4],
[192, 192, 3, 3, True, 1, 4],
[192, 192, 3, 3, True, 1, 4],
[192, 192, 3, 3, True, 1, 4],
[192, 192, 3, 5, True, 1, 4],
[192, 192, 5, 3, True, 1, 4],
[192, 192, 5, 3, True, 1, 4],
[192, 192, 5, 3, True, 1, 4],
[192, 192, 5, 3, True, 1, 4],
[192, 192, 5, 3, True, 1, 4],
[192, 192, 3, 0, True, 1, 4]
]
},
"layer4": {
"block_name": "uib",
"num_blocks": 13,
"block_specs": [
[192, 512, 5, 5, True, 2, 4],
[512, 512, 5, 5, True, 1, 4],
[512, 512, 5, 5, True, 1, 4],
[512, 512, 5, 5, True, 1, 4],
[512, 512, 5, 0, True, 1, 4],
[512, 512, 5, 3, True, 1, 4],
[512, 512, 5, 0, True, 1, 4],
[512, 512, 5, 0, True, 1, 4],
[512, 512, 5, 3, True, 1, 4],
[512, 512, 5, 5, True, 1, 4],
[512, 512, 5, 0, True, 1, 4],
[512, 512, 5, 0, True, 1, 4],
[512, 512, 5, 0, True, 1, 4]
]
},
"layer5": {
"block_name": "convbn",
"num_blocks": 2,
"block_specs": [
[512, 960, 1, 1],
[960, 1280, 1, 1]
]
}
}
MNV4HybridConvMedium_BLOCK_SPECS = {
}
MNV4HybridConvLarge_BLOCK_SPECS = {
}
MODEL_SPECS = {
"MobileNetV4ConvSmall": MNV4ConvSmall_BLOCK_SPECS,
"MobileNetV4ConvMedium": MNV4ConvMedium_BLOCK_SPECS,
"MobileNetV4ConvLarge": MNV4ConvLarge_BLOCK_SPECS,
"MobileNetV4HybridMedium": MNV4HybridConvMedium_BLOCK_SPECS,
"MobileNetV4HybridLarge": MNV4HybridConvLarge_BLOCK_SPECS,
}
def make_divisible(
value: float,
divisor: int,
min_value: Optional[float] = None,
round_down_protect: bool = True,
) -> int:
"""
This function is copied from here
"https://github.com/tensorflow/models/blob/master/official/vision/modeling/layers/nn_layers.py"
This is to ensure that all layers have channels that are divisible by 8.
Args:
value: A `float` of original value.
divisor: An `int` of the divisor that need to be checked upon.
min_value: A `float` of minimum value threshold.
round_down_protect: A `bool` indicating whether round down more than 10%
will be allowed.
Returns:
The adjusted value in `int` that is divisible against divisor.
"""
if min_value is None:
min_value = divisor
new_value = max(min_value, int(value + divisor / 2) // divisor * divisor)
# Make sure that round down does not go down by more than 10%.
if round_down_protect and new_value < 0.9 * value:
new_value += divisor
return int(new_value)
def conv_2d(inp, oup, kernel_size=3, stride=1, groups=1, bias=False, norm=True, act=True):
conv = nn.Sequential()
padding = (kernel_size - 1) // 2
conv.add_module('conv', nn.Conv2d(inp, oup, kernel_size, stride, padding, bias=bias, groups=groups))
if norm:
conv.add_module('BatchNorm2d', nn.BatchNorm2d(oup))
if act:
conv.add_module('Activation', nn.ReLU6())
return conv
class InvertedResidual(nn.Module):
def __init__(self, inp, oup, stride, expand_ratio, act=False):
super(InvertedResidual, self).__init__()
self.stride = stride
assert stride in [1, 2]
hidden_dim = int(round(inp * expand_ratio))
self.block = nn.Sequential()
if expand_ratio != 1:
self.block.add_module('exp_1x1', conv_2d(inp, hidden_dim, kernel_size=1, stride=1))
self.block.add_module('conv_3x3', conv_2d(hidden_dim, hidden_dim, kernel_size=3, stride=stride, groups=hidden_dim))
self.block.add_module('red_1x1', conv_2d(hidden_dim, oup, kernel_size=1, stride=1, act=act))
self.use_res_connect = self.stride == 1 and inp == oup
def forward(self, x):
if self.use_res_connect:
return x + self.block(x)
else:
return self.block(x)
class UniversalInvertedBottleneckBlock(nn.Module):
def __init__(self,
inp,
oup,
start_dw_kernel_size,
middle_dw_kernel_size,
middle_dw_downsample,
stride,
expand_ratio
):
super().__init__()
# Starting depthwise conv.
self.start_dw_kernel_size = start_dw_kernel_size
if self.start_dw_kernel_size:
stride_ = stride if not middle_dw_downsample else 1
self._start_dw_ = conv_2d(inp, inp, kernel_size=start_dw_kernel_size, stride=stride_, groups=inp, act=False)
# Expansion with 1x1 convs.
expand_filters = make_divisible(inp * expand_ratio, 8)
self._expand_conv = conv_2d(inp, expand_filters, kernel_size=1)
# Middle depthwise conv.
self.middle_dw_kernel_size = middle_dw_kernel_size
if self.middle_dw_kernel_size:
stride_ = stride if middle_dw_downsample else 1
self._middle_dw = conv_2d(expand_filters, expand_filters, kernel_size=middle_dw_kernel_size, stride=stride_, groups=expand_filters)
# Projection with 1x1 convs.
self._proj_conv = conv_2d(expand_filters, oup, kernel_size=1, stride=1, act=False)
# Ending depthwise conv.
# this not used
# _end_dw_kernel_size = 0
# self._end_dw = conv_2d(oup, oup, kernel_size=_end_dw_kernel_size, stride=stride, groups=inp, act=False)
def forward(self, x):
if self.start_dw_kernel_size:
x = self._start_dw_(x)
# print("_start_dw_", x.shape)
x = self._expand_conv(x)
# print("_expand_conv", x.shape)
if self.middle_dw_kernel_size:
x = self._middle_dw(x)
# print("_middle_dw", x.shape)
x = self._proj_conv(x)
# print("_proj_conv", x.shape)
return x
def build_blocks(layer_spec):
if not layer_spec.get('block_name'):
return nn.Sequential()
block_names = layer_spec['block_name']
layers = nn.Sequential()
if block_names == "convbn":
schema_ = ['inp', 'oup', 'kernel_size', 'stride']
args = {}
for i in range(layer_spec['num_blocks']):
args = dict(zip(schema_, layer_spec['block_specs'][i]))
layers.add_module(f"convbn_{i}", conv_2d(**args))
elif block_names == "uib":
schema_ = ['inp', 'oup', 'start_dw_kernel_size', 'middle_dw_kernel_size', 'middle_dw_downsample', 'stride', 'expand_ratio']
args = {}
for i in range(layer_spec['num_blocks']):
args = dict(zip(schema_, layer_spec['block_specs'][i]))
layers.add_module(f"uib_{i}", UniversalInvertedBottleneckBlock(**args))
elif block_names == "fused_ib":
schema_ = ['inp', 'oup', 'stride', 'expand_ratio', 'act']
args = {}
for i in range(layer_spec['num_blocks']):
args = dict(zip(schema_, layer_spec['block_specs'][i]))
layers.add_module(f"fused_ib_{i}", InvertedResidual(**args))
else:
raise NotImplementedError
return layers
class MobileNetV4(nn.Module):
def __init__(self, model):
# MobileNetV4ConvSmall MobileNetV4ConvMedium MobileNetV4ConvLarge
# MobileNetV4HybridMedium MobileNetV4HybridLarge
"""Params to initiate MobilenNetV4
Args:
model : support 5 types of models as indicated in
"https://github.com/tensorflow/models/blob/master/official/vision/modeling/backbones/mobilenet.py"
"""
super().__init__()
assert model in MODEL_SPECS.keys()
self.model = model
self.spec = MODEL_SPECS[self.model]
# conv0
self.conv0 = build_blocks(self.spec['conv0'])
# layer1
self.layer1 = build_blocks(self.spec['layer1'])
# layer2
self.layer2 = build_blocks(self.spec['layer2'])
# layer3
self.layer3 = build_blocks(self.spec['layer3'])
# layer4
self.layer4 = build_blocks(self.spec['layer4'])
# layer5
self.layer5 = build_blocks(self.spec['layer5'])
self.features = nn.ModuleList([self.conv0, self.layer1, self.layer2, self.layer3, self.layer4, self.layer5])
self.channel = [i.size(1) for i in self.forward(torch.randn(1, 3, 640, 640))]
def forward(self, x):
input_size = x.size(2)
scale = [4, 8, 16, 32]
features = [None, None, None, None]
for f in self.features:
x = f(x)
if input_size // x.size(2) in scale:
features[scale.index(input_size // x.size(2))] = x
return features
def MobileNetV4ConvSmall():
model = MobileNetV4('MobileNetV4ConvSmall')
return model
def MobileNetV4ConvMedium():
model = MobileNetV4('MobileNetV4ConvMedium')
return model
def MobileNetV4ConvLarge():
model = MobileNetV4('MobileNetV4ConvLarge')
return model
def MobileNetV4HybridMedium():
model = MobileNetV4('MobileNetV4HybridMedium')
return model
def MobileNetV4HybridLarge():
model = MobileNetV4('MobileNetV4HybridLarge')
return model
if __name__ == '__main__':
model = MobileNetV4ConvSmall()
inputs = torch.randn((1, 3, 640, 640))
res = model(inputs)
for i in res:
print(i.size())第②步：修改task.py
(1)引入创建的MobileNetV4文件
from ultralytics.nn.backbone.mobilenetv4 import *(2)修改_predict_once函数
可直接将下述代码替换对应位置
def _predict_once(self, x, profile=False, visualize=False, embed=None):
"""
Perform a forward pass through the network.
Args:
x (torch.Tensor): The input tensor to the model.
profile (bool): Print the computation time of each layer if True, defaults to False.
visualize (bool): Save the feature maps of the model if True, defaults to False.
embed (list, optional): A list of feature vectors/embeddings to return.
Returns:
(torch.Tensor): The last output of the model.
"""
y, dt, embeddings = [], [], [] # outputs
for idx, m in enumerate(self.model):
if m.f != -1: # if not from previous layer
x = y[m.f] if isinstance(m.f, int) else [x if j == -1 else y[j] for j in m.f] # from earlier layers
if profile:
self._profile_one_layer(m, x, dt)
if hasattr(m, 'backbone'):
x = m(x)
for _ in range(5 - len(x)):
x.insert(0, None)
for i_idx, i in enumerate(x):
if i_idx in self.save:
y.append(i)
else:
y.append(None)
# print(f'layer id:{idx:>2} {m.type:>50} output shape:{", ".join([str(x_.size()) for x_ in x if x_ is not None])}')
x = x[-1]
else:
x = m(x) # run
y.append(x if m.i in self.save else None) # save output
# if type(x) in {list, tuple}:
# if idx == (len(self.model) - 1):
# if type(x[1]) is dict:
# print(f'layer id:{idx:>2} {m.type:>50} output shape:{", ".join([str(x_.size()) for x_ in x[1]["one2one"]])}')
# else:
# print(f'layer id:{idx:>2} {m.type:>50} output shape:{", ".join([str(x_.size()) for x_ in x[1]])}')
# else:
# print(f'layer id:{idx:>2} {m.type:>50} output shape:{", ".join([str(x_.size()) for x_ in x if x_ is not None])}')
# elif type(x) is dict:
# print(f'layer id:{idx:>2} {m.type:>50} output shape:{", ".join([str(x_.size()) for x_ in x["one2one"]])}')
# else:
# if not hasattr(m, 'backbone'):
# print(f'layer id:{idx:>2} {m.type:>50} output shape:{x.size()}')
if visualize:
feature_visualization(x, m.type, m.i, save_dir=visualize)
if embed and m.i in embed:
embeddings.append(nn.functional.adaptive_avg_pool2d(x, (1, 1)).squeeze(-1).squeeze(-1)) # flatten
if m.i == max(embed):
return torch.unbind(torch.cat(embeddings, 1), dim=0)
return x(3)修改parse_model函数
可以直接把下面的代码粘贴到对应的位置中
def parse_model(d, ch, verbose=True): # model_dict, input_channels(3)
"""
Parse a YOLO model.yaml dictionary into a PyTorch model.
Args:
d (dict): Model dictionary.
ch (int): Input channels.
verbose (bool): Whether to print model details.
Returns:
(tuple): Tuple containing the PyTorch model and sorted list of output layers.
"""
import ast
# Args
max_channels = float("inf")
nc, act, scales = (d.get(x) for x in ("nc", "activation", "scales"))
depth, width, kpt_shape = (d.get(x, 1.0) for x in ("depth_multiple", "width_multiple", "kpt_shape"))
if scales:
scale = d.get("scale")
if not scale:
scale = tuple(scales.keys())[0]
LOGGER.warning(f"WARNING ⚠️ no model scale passed. Assuming scale='{scale}'.")
if len(scales[scale]) == 3:
depth, width, max_channels = scales[scale]
elif len(scales[scale]) == 4:
depth, width, max_channels, threshold = scales[scale]
if act:
Conv.default_act = eval(act) # redefine default activation, i.e. Conv.default_act = nn.SiLU()
if verbose:
LOGGER.info(f"{colorstr('activation:')} {act}") # print
if verbose:
LOGGER.info(f"\n{'':>3}{'from':>20}{'n':>3}{'params':>10} {'module':<60}{'arguments':<50}")
ch = [ch]
layers, save, c2 = [], [], ch[-1] # layers, savelist, ch out
is_backbone = False
for i, (f, n, m, args) in enumerate(d["backbone"] + d["head"]): # from, number, module, args
try:
if m == 'node_mode':
m = d[m]
if len(args) > 0:
if args[0] == 'head_channel':
args[0] = int(d[args[0]])
t = m
m = getattr(torch.nn, m[3:]) if 'nn.' in m else globals()[m] # get module
except:
pass
for j, a in enumerate(args):
if isinstance(a, str):
with contextlib.suppress(ValueError):
try:
args[j] = locals()[a] if a in locals() else ast.literal_eval(a)
except:
args[j] = a
n = n_ = max(round(n * depth), 1) if n > 1 else n # depth gain
if m in {
Classify, Conv, ConvTranspose, GhostConv, Bottleneck, GhostBottleneck, SPP, SPPF, DWConv, Focus,
BottleneckCSP, C1, C2, C2f, ELAN1, AConv, SPPELAN, C2fAttn, C3, C3TR,
C3Ghost, nn.Conv2d, nn.ConvTranspose2d, DWConvTranspose2d, C3x, RepC3, PSA, SCDown, C2fCIB
}:
if args[0] == 'head_channel':
args[0] = d[args[0]]
c1, c2 = ch[f], args[0]
if c2 != nc: # if c2 not equal to number of classes (i.e. for Classify() output)
c2 = make_divisible(min(c2, max_channels) * width, 8)
if m is C2fAttn:
args[1] = make_divisible(min(args[1], max_channels // 2) * width, 8) # embed channels
args[2] = int(
max(round(min(args[2], max_channels // 2 // 32)) * width, 1) if args[2] > 1 else args[2]
) # num heads
args = [c1, c2, *args[1:]]
elif m in {AIFI}:
args = [ch[f], *args]
c2 = args[0]
elif m in (HGStem, HGBlock):
c1, cm, c2 = ch[f], args[0], args[1]
if c2 != nc: # if c2 not equal to number of classes (i.e. for Classify() output)
c2 = make_divisible(min(c2, max_channels) * width, 8)
cm = make_divisible(min(cm, max_channels) * width, 8)
args = [c1, cm, c2, *args[2:]]
if m in (HGBlock):
args.insert(4, n) # number of repeats
n = 1
elif m is ResNetLayer:
c2 = args[1] if args[3] else args[1] * 4
elif m is nn.BatchNorm2d:
args = [ch[f]]
elif m is Concat:
c2 = sum(ch[x] for x in f)
elif m in frozenset({Detect, WorldDetect, Segment, Pose, OBB, ImagePoolingAttn, v10Detect}):
args.append([ch[x] for x in f])
elif m is RTDETRDecoder: # special case, channels arg must be passed in index 1
args.insert(1, [ch[x] for x in f])
elif m is CBLinear:
c2 = make_divisible(min(args[0][-1], max_channels) * width, 8)
c1 = ch[f]
args = [c1, [make_divisible(min(c2_, max_channels) * width, 8) for c2_ in args[0]], *args[1:]]
elif m is CBFuse:
c2 = ch[f[-1]]
elif isinstance(m, str):
t = m
if len(args) == 2:
m = timm.create_model(m, pretrained=args[0], pretrained_cfg_overlay={'file': args[1]},
features_only=True)
elif len(args) == 1:
m = timm.create_model(m, pretrained=args[0], features_only=True)
c2 = m.feature_info.channels()
elif m in {MobileNetV4ConvSmall, MobileNetV4ConvMedium, MobileNetV4ConvLarge, MobileNetV4HybridMedium, MobileNetV4HybridLarge
}:
m = m(*args)
c2 = m.channel
else:
c2 = ch[f]
if isinstance(c2, list):
is_backbone = True
m_ = m
m_.backbone = True
else:
m_ = nn.Sequential(*(m(*args) for _ in range(n))) if n > 1 else m(*args) # module
t = str(m)[8:-2].replace('__main__.', '') # module type
m.np = sum(x.numel() for x in m_.parameters()) # number params
m_.i, m_.f, m_.type = i + 4 if is_backbone else i, f, t # attach index, 'from' index, type
if verbose:
LOGGER.info(f"{i:>3}{str(f):>20}{n_:>3}{m.np:10.0f} {t:<60}{str(args):<50}") # print
save.extend(x % (i + 4 if is_backbone else i) for x in ([f] if isinstance(f, int) else f) if
x != -1) # append to savelist
layers.append(m_)
if i == 0:
ch = []
if isinstance(c2, list):
ch.extend(c2)
for _ in range(5 - len(ch)):
ch.insert(0, 0)
else:
ch.append(c2)
return nn.Sequential(*layers), sorted(save)具体改进差别如下图所示: 
第③步：yolov8.yaml文件修改
在下述文件夹中创立yolov8-mobilenetv4.yaml
# 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
# 0-P1/2
# 1-P2/4
# 2-P3/8
# 3-P4/16
# 4-P5/32
# YOLOv8.0n backbone
backbone:
# [from, repeats, module, args]
- [-1, 1, MobileNetV4ConvSmall, []] # 4
- [-1, 1, SPPF, [1024, 5]] # 5
# YOLOv8.0n head
head:
- [-1, 1, nn.Upsample, [None, 2, 'nearest']] # 6
- [[-1, 3], 1, Concat, [1]] # 7 cat backbone P4
- [-1, 3, C2f, [512]] # 8
- [-1, 1, nn.Upsample, [None, 2, 'nearest']] # 9
- [[-1, 2], 1, Concat, [1]] # 10 cat backbone P3
- [-1, 3, C2f, [256]] # 11 (P3/8-small)
- [-1, 1, Conv, [256, 3, 2]] # 12
- [[-1, 8], 1, Concat, [1]] # 13 cat head P4
- [-1, 3, C2f, [512]] # 14 (P4/16-medium)
- [-1, 1, Conv, [512, 3, 2]] # 15
- [[-1, 5], 1, Concat, [1]] # 16 cat head P5
- [-1, 3, C2f, [1024]] # 17 (P5/32-large)
- [[11, 14, 17], 1, Detect, [nc]] # Detect(P3, P4, P5)第④步：验证是否加入成功
将train.py中的配置文件进行修改，并运行 
【YOLOv8改进系列】：
YOLOv8改进系列（1）----替换主干网络之EfficientViT(CVPR2023)
YOLOv8改进系列（2）----替换主干网络之FasterNet
YOLOv8改进系列（3）----替换主干网络之ConvNeXt V2
YOLOv8改进系列（4）----替换C2f之FasterNet中的FasterBlock替换C2f中的Bottleneck
YOLOv8改进系列（5）----替换主干网络之EfficientFormerV2
YOLOv8改进系列（6）----替换主干网络之VanillaNet
YOLOv8改进系列（7）----替换主干网络之LSKNet
YOLOv8改进系列（8）----替换主干网络之Swin Transformer
YOLOv8改进系列（9）----替换主干网络之RepViT
YOLOv8改进系列（10）----替换主干网络之UniRepLKNet
