一、本文介绍
本文给大家带来的改进机制是利用图像分割网络UNetV2的主干来改进我们的YOLOv8分割模型**（本文的内容虽然YOLOv8所有的功能的用户都能使用，但是还是建议分割的用户使用），**U-Net v2 旨在改进医学图像分割的性能，通过引入一种新的、更为高效的跳跃连接设计来实现。这个版本的U-Net专注于更好地融合来自不同层级的特征------既包括从高级特征中提取的语义信息，也包括从低级特征中提取的细节信息。通过这种方式，U-Net v2能够在低级特征中注入丰富的语义信息，并同时精细化高级特征，从而实现对医学图像中对象边界的精确勾画和小结构的有效提取。
欢迎大家订阅我的专栏一起学习YOLO！
专栏目录：************************************************************YOLOv8改进有效系列目录 | 包含卷积、主干、检测头、注意力机制、Neck上百种创新机制****************************************************************
目录
[4.1 修改一](#4.1 修改一)
[4.2 修改二](#4.2 修改二)
[4.3 修改三](#4.3 修改三)
[4.4 修改四](#4.4 修改四)
[4.5 修改五](#4.5 修改五)
[4.6 修改六](#4.6 修改六)
[4.7 修改七](#4.7 修改七)
[4.8 修改八](#4.8 修改八)
[注意！！！ 额外的修改！](#注意！！！ 额外的修改！)
[5.1 UNetV2的yaml文件](#5.1 UNetV2的yaml文件)
[5.2 训练文件的代码](#5.2 训练文件的代码)
二、原理介绍
官方论文地址：官方论文地址点击此处即可跳转
官方代码地址：官方代码地址点击此处即可跳转
U-Net v2 旨在改进医学图像分割的性能，通过引入一种新的、更为高效的跳跃连接设计来实现。这个版本的U-Net专注于更好地融合来自不同层级的特征------既包括从高级特征中提取的语义信息，也包括从低级特征中提取的细节信息。通过这种方式，U-Net v2能够在低级特征中注入丰富的语义信息，并同时精细化高级特征，从而实现对医学图像中对象边界的精确勾画和小结构的有效提取。
关键的技术创新包括：
- **多级特征提取：**使用深度神经网络编码器从输入图像中提取多级特征。
- **语义与细节融合(Semantics and Detail Infusion, SDI)模块：**通过哈达玛积操作，将高级特征中的语义信息和低级特征中的细节信息融合到每个层级的特征图中。
- **改进的跳跃连接：**这些新型的跳跃连接能够提升所有层级特征的语义特性和细节复杂性，从而在解码器进行更进一步的处理和分割时，能够实现更准确的分割效果。
U-Net v2的另一个亮点是其高效性，它在保持计算和内存效率的同时，显著提高了分割任务的准确度。这一点通过在多个公开的医学图像分割数据集上的评估得到了验证，包括皮肤病变分割和息肉分割等任务。实验结果显示，U-Net v2在这些任务上均优于现有的最先进方法。
此外，U-Net v2的设计支持它可以无缝集成到任何编码器-解码器网络架构中，提供了良好的通用性和灵活性。研究者还提供了U-Net v2的开源代码，便于社区进一步研究和应用。
总结而言，U-Net v2为医学图像分割领域带来了一种新的、高效且准确的模型架构，特别是在处理有限数据条件下的医学图像时，展现了其强大的性能和应用潜力。
三、核心代码
此处声明一下：UNet是一整个模型类似于YOLO这样，我们这里是采用了UNetV2的主干进行实验，其中其Neck部分主要提出了SDI我之前发过这个机制，大家应该有用过。
import os.path
import warnings
import torch
import torch.nn as nn
import torch.nn.functional as F
from functools import partial
from timm.models.layers import DropPath, to_2tuple, trunc_normal_
import math
__all__ = ['pvt_v2_b0', 'pvt_v2_b1', 'pvt_v2_b2', 'pvt_v2_b3', 'pvt_v2_b4', 'pvt_v2_b5']
class ChannelAttention(nn.Module):
def __init__(self, in_planes, ratio=16):
super(ChannelAttention, self).__init__()
self.avg_pool = nn.AdaptiveAvgPool2d(1)
self.max_pool = nn.AdaptiveMaxPool2d(1)
self.fc1 = nn.Conv2d(in_planes, in_planes // 16, 1, bias=False)
self.relu1 = nn.ReLU()
self.fc2 = nn.Conv2d(in_planes // 16, in_planes, 1, bias=False)
self.sigmoid = nn.Sigmoid()
def forward(self, x):
avg_out = self.fc2(self.relu1(self.fc1(self.avg_pool(x))))
max_out = self.fc2(self.relu1(self.fc1(self.max_pool(x))))
out = avg_out + max_out
return self.sigmoid(out)
class SpatialAttention(nn.Module):
def __init__(self, kernel_size=7):
super(SpatialAttention, self).__init__()
assert kernel_size in (3, 7), 'kernel size must be 3 or 7'
padding = 3 if kernel_size == 7 else 1
self.conv1 = nn.Conv2d(2, 1, kernel_size, padding=padding, bias=False)
self.sigmoid = nn.Sigmoid()
def forward(self, x):
avg_out = torch.mean(x, dim=1, keepdim=True)
max_out, _ = torch.max(x, dim=1, keepdim=True)
x = torch.cat([avg_out, max_out], dim=1)
x = self.conv1(x)
return self.sigmoid(x)
class BasicConv2d(nn.Module):
def __init__(self, in_planes, out_planes, kernel_size, stride=1, padding=0, dilation=1):
super(BasicConv2d, self).__init__()
self.conv = nn.Conv2d(in_planes, out_planes,
kernel_size=kernel_size, stride=stride,
padding=padding, dilation=dilation, bias=False)
self.bn = nn.BatchNorm2d(out_planes)
self.relu = nn.ReLU(inplace=True)
def forward(self, x):
x = self.conv(x)
x = self.bn(x)
return x
class Encoder(nn.Module):
def __init__(self, pretrain_path):
super().__init__()
self.backbone = pvt_v2_b2()
if pretrain_path is None:
warnings.warn('please provide the pretrained pvt model. Not using pretrained model.')
elif not os.path.isfile(pretrain_path):
warnings.warn(f'path: {pretrain_path} does not exists. Not using pretrained model.')
else:
print(f"using pretrained file: {pretrain_path}")
save_model = torch.load(pretrain_path)
model_dict = self.backbone.state_dict()
state_dict = {k: v for k, v in save_model.items() if k in model_dict.keys()}
model_dict.update(state_dict)
self.backbone.load_state_dict(model_dict)
def forward(self, x):
f1, f2, f3, f4 = self.backbone(x) # (x: 3, 352, 352)
return f1, f2, f3, f4
class SDI(nn.Module):
def __init__(self, channel):
super().__init__()
self.convs = nn.ModuleList(
[nn.Conv2d(channel, channel, kernel_size=3, stride=1, padding=1) for _ in range(4)])
def forward(self, xs, anchor):
ans = torch.ones_like(anchor)
target_size = anchor.shape[-1]
for i, x in enumerate(xs):
if x.shape[-1] > target_size:
x = F.adaptive_avg_pool2d(x, (target_size, target_size))
elif x.shape[-1] < target_size:
x = F.interpolate(x, size=(target_size, target_size),
mode='bilinear', align_corners=True)
ans = ans * self.convs[i](x)
return ans
class UNetV2(nn.Module):
"""
use SpatialAtt + ChannelAtt
"""
def __init__(self, channel=3, n_classes=1, deep_supervision=True, pretrained_path=None):
super().__init__()
self.deep_supervision = deep_supervision
self.encoder = Encoder(pretrained_path)
self.ca_1 = ChannelAttention(64)
self.sa_1 = SpatialAttention()
self.ca_2 = ChannelAttention(128)
self.sa_2 = SpatialAttention()
self.ca_3 = ChannelAttention(320)
self.sa_3 = SpatialAttention()
self.ca_4 = ChannelAttention(512)
self.sa_4 = SpatialAttention()
self.Translayer_1 = BasicConv2d(64, channel, 1)
self.Translayer_2 = BasicConv2d(128, channel, 1)
self.Translayer_3 = BasicConv2d(320, channel, 1)
self.Translayer_4 = BasicConv2d(512, channel, 1)
self.sdi_1 = SDI(channel)
self.sdi_2 = SDI(channel)
self.sdi_3 = SDI(channel)
self.sdi_4 = SDI(channel)
self.seg_outs = nn.ModuleList([
nn.Conv2d(channel, n_classes, 1, 1) for _ in range(4)])
self.deconv2 = nn.ConvTranspose2d(channel, channel, kernel_size=4, stride=2, padding=1,
bias=False)
self.deconv3 = nn.ConvTranspose2d(channel, channel, kernel_size=4, stride=2,
padding=1, bias=False)
self.deconv4 = nn.ConvTranspose2d(channel, channel, kernel_size=4, stride=2,
padding=1, bias=False)
self.deconv5 = nn.ConvTranspose2d(channel, channel, kernel_size=4, stride=2,
padding=1, bias=False)
self.width_list = [i.size(1) for i in self.forward(torch.randn(1, 3, 640, 640))]
def forward(self, x):
seg_outs = []
f1, f2, f3, f4 = self.encoder(x)
f1 = self.ca_1(f1) * f1
f1 = self.sa_1(f1) * f1
f1 = self.Translayer_1(f1)
f2 = self.ca_2(f2) * f2
f2 = self.sa_2(f2) * f2
f2 = self.Translayer_2(f2)
f3 = self.ca_3(f3) * f3
f3 = self.sa_3(f3) * f3
f3 = self.Translayer_3(f3)
f4 = self.ca_4(f4) * f4
f4 = self.sa_4(f4) * f4
f4 = self.Translayer_4(f4)
f41 = self.sdi_4([f1, f2, f3, f4], f4)
f31 = self.sdi_3([f1, f2, f3, f4], f3)
f21 = self.sdi_2([f1, f2, f3, f4], f2)
f11 = self.sdi_1([f1, f2, f3, f4], f1)
seg_outs.append(self.seg_outs[0](f41))
y = self.deconv2(f41) + f31
seg_outs.append(self.seg_outs[1](y))
y = self.deconv3(y) + f21
seg_outs.append(self.seg_outs[2](y))
y = self.deconv4(y) + f11
seg_outs.append(self.seg_outs[3](y))
for i, o in enumerate(seg_outs):
seg_outs[i] = F.interpolate(o, scale_factor=4, mode='bilinear')
if self.deep_supervision:
return seg_outs[::-1]
else:
return seg_outs[-1]
class Mlp(nn.Module):
def __init__(self, in_features, hidden_features=None, out_features=None, act_layer=nn.GELU, drop=0.):
super().__init__()
out_features = out_features or in_features
hidden_features = hidden_features or in_features
self.fc1 = nn.Linear(in_features, hidden_features)
self.dwconv = DWConv(hidden_features)
self.act = act_layer()
self.fc2 = nn.Linear(hidden_features, out_features)
self.drop = nn.Dropout(drop)
self.apply(self._init_weights)
def _init_weights(self, m):
if isinstance(m, nn.Linear):
trunc_normal_(m.weight, std=.02)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
elif isinstance(m, nn.Conv2d):
fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
fan_out //= m.groups
m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
if m.bias is not None:
m.bias.data.zero_()
def forward(self, x, H, W):
x = self.fc1(x)
x = self.dwconv(x, H, W)
x = self.act(x)
x = self.drop(x)
x = self.fc2(x)
x = self.drop(x)
return x
class Attention(nn.Module):
def __init__(self, dim, num_heads=8, qkv_bias=False, qk_scale=None, attn_drop=0., proj_drop=0., sr_ratio=1):
super().__init__()
assert dim % num_heads == 0, f"dim {dim} should be divided by num_heads {num_heads}."
self.dim = dim
self.num_heads = num_heads
head_dim = dim // num_heads
self.scale = qk_scale or head_dim ** -0.5
self.q = nn.Linear(dim, dim, bias=qkv_bias)
self.kv = nn.Linear(dim, dim * 2, bias=qkv_bias)
self.attn_drop = nn.Dropout(attn_drop)
self.proj = nn.Linear(dim, dim)
self.proj_drop = nn.Dropout(proj_drop)
self.sr_ratio = sr_ratio
if sr_ratio > 1:
self.sr = nn.Conv2d(dim, dim, kernel_size=sr_ratio, stride=sr_ratio)
self.norm = nn.LayerNorm(dim)
self.apply(self._init_weights)
def _init_weights(self, m):
if isinstance(m, nn.Linear):
trunc_normal_(m.weight, std=.02)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
elif isinstance(m, nn.Conv2d):
fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
fan_out //= m.groups
m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
if m.bias is not None:
m.bias.data.zero_()
def forward(self, x, H, W):
B, N, C = x.shape
q = self.q(x).reshape(B, N, self.num_heads, C // self.num_heads).permute(0, 2, 1, 3)
if self.sr_ratio > 1:
x_ = x.permute(0, 2, 1).reshape(B, C, H, W)
x_ = self.sr(x_).reshape(B, C, -1).permute(0, 2, 1)
x_ = self.norm(x_)
kv = self.kv(x_).reshape(B, -1, 2, self.num_heads, C // self.num_heads).permute(2, 0, 3, 1, 4)
else:
kv = self.kv(x).reshape(B, -1, 2, self.num_heads, C // self.num_heads).permute(2, 0, 3, 1, 4)
k, v = kv[0], kv[1]
attn = (q @ k.transpose(-2, -1)) * self.scale
attn = attn.softmax(dim=-1)
attn = self.attn_drop(attn)
x = (attn @ v).transpose(1, 2).reshape(B, N, C)
x = self.proj(x)
x = self.proj_drop(x)
return x
class Block(nn.Module):
def __init__(self, dim, num_heads, mlp_ratio=4., qkv_bias=False, qk_scale=None, drop=0., attn_drop=0.,
drop_path=0., act_layer=nn.GELU, norm_layer=nn.LayerNorm, sr_ratio=1):
super().__init__()
self.norm1 = norm_layer(dim)
self.attn = Attention(
dim,
num_heads=num_heads, qkv_bias=qkv_bias, qk_scale=qk_scale,
attn_drop=attn_drop, proj_drop=drop, sr_ratio=sr_ratio)
# NOTE: drop path for stochastic depth, we shall see if this is better than dropout here
self.drop_path = DropPath(drop_path) if drop_path > 0. else nn.Identity()
self.norm2 = norm_layer(dim)
mlp_hidden_dim = int(dim * mlp_ratio)
self.mlp = Mlp(in_features=dim, hidden_features=mlp_hidden_dim, act_layer=act_layer, drop=drop)
self.apply(self._init_weights)
def _init_weights(self, m):
if isinstance(m, nn.Linear):
trunc_normal_(m.weight, std=.02)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
elif isinstance(m, nn.Conv2d):
fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
fan_out //= m.groups
m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
if m.bias is not None:
m.bias.data.zero_()
def forward(self, x, H, W):
x = x + self.drop_path(self.attn(self.norm1(x), H, W))
x = x + self.drop_path(self.mlp(self.norm2(x), H, W))
return x
class OverlapPatchEmbed(nn.Module):
""" Image to Patch Embedding
"""
def __init__(self, img_size=224, patch_size=7, stride=4, in_chans=3, embed_dim=768):
super().__init__()
img_size = to_2tuple(img_size)
patch_size = to_2tuple(patch_size)
self.img_size = img_size
self.patch_size = patch_size
self.H, self.W = img_size[0] // patch_size[0], img_size[1] // patch_size[1]
self.num_patches = self.H * self.W
self.proj = nn.Conv2d(in_chans, embed_dim, kernel_size=patch_size, stride=stride,
padding=(patch_size[0] // 2, patch_size[1] // 2))
self.norm = nn.LayerNorm(embed_dim)
self.apply(self._init_weights)
def _init_weights(self, m):
if isinstance(m, nn.Linear):
trunc_normal_(m.weight, std=.02)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
elif isinstance(m, nn.Conv2d):
fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
fan_out //= m.groups
m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
if m.bias is not None:
m.bias.data.zero_()
def forward(self, x):
x = self.proj(x)
_, _, H, W = x.shape
x = x.flatten(2).transpose(1, 2)
x = self.norm(x)
return x, H, W
class PyramidVisionTransformerImpr(nn.Module):
def __init__(self, img_size=224, patch_size=16, in_chans=3, num_classes=1000, embed_dims=[64, 128, 256, 512],
num_heads=[1, 2, 4, 8], mlp_ratios=[4, 4, 4, 4], qkv_bias=False, qk_scale=None, drop_rate=0.,
attn_drop_rate=0., drop_path_rate=0., norm_layer=nn.LayerNorm,
depths=[3, 4, 6, 3], sr_ratios=[8, 4, 2, 1]):
super().__init__()
self.num_classes = num_classes
self.depths = depths
# patch_embed
self.patch_embed1 = OverlapPatchEmbed(img_size=img_size, patch_size=7, stride=4, in_chans=in_chans,
embed_dim=embed_dims[0])
self.patch_embed2 = OverlapPatchEmbed(img_size=img_size // 4, patch_size=3, stride=2, in_chans=embed_dims[0],
embed_dim=embed_dims[1])
self.patch_embed3 = OverlapPatchEmbed(img_size=img_size // 8, patch_size=3, stride=2, in_chans=embed_dims[1],
embed_dim=embed_dims[2])
self.patch_embed4 = OverlapPatchEmbed(img_size=img_size // 16, patch_size=3, stride=2, in_chans=embed_dims[2],
embed_dim=embed_dims[3])
# transformer encoder
dpr = [x.item() for x in torch.linspace(0, drop_path_rate, sum(depths))] # stochastic depth decay rule
cur = 0
self.block1 = nn.ModuleList([Block(
dim=embed_dims[0], num_heads=num_heads[0], mlp_ratio=mlp_ratios[0], qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[cur + i], norm_layer=norm_layer,
sr_ratio=sr_ratios[0])
for i in range(depths[0])])
self.norm1 = norm_layer(embed_dims[0])
cur += depths[0]
self.block2 = nn.ModuleList([Block(
dim=embed_dims[1], num_heads=num_heads[1], mlp_ratio=mlp_ratios[1], qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[cur + i], norm_layer=norm_layer,
sr_ratio=sr_ratios[1])
for i in range(depths[1])])
self.norm2 = norm_layer(embed_dims[1])
cur += depths[1]
self.block3 = nn.ModuleList([Block(
dim=embed_dims[2], num_heads=num_heads[2], mlp_ratio=mlp_ratios[2], qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[cur + i], norm_layer=norm_layer,
sr_ratio=sr_ratios[2])
for i in range(depths[2])])
self.norm3 = norm_layer(embed_dims[2])
cur += depths[2]
self.block4 = nn.ModuleList([Block(
dim=embed_dims[3], num_heads=num_heads[3], mlp_ratio=mlp_ratios[3], qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[cur + i], norm_layer=norm_layer,
sr_ratio=sr_ratios[3])
for i in range(depths[3])])
self.norm4 = norm_layer(embed_dims[3])
# classification head
# self.head = nn.Linear(embed_dims[3], num_classes) if num_classes > 0 else nn.Identity()
self.apply(self._init_weights)
self.width_list = [i.size(1) for i in self.forward(torch.randn(1, 3, 640, 640))]
def _init_weights(self, m):
if isinstance(m, nn.Linear):
trunc_normal_(m.weight, std=.02)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
elif isinstance(m, nn.Conv2d):
fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
fan_out //= m.groups
m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
if m.bias is not None:
m.bias.data.zero_()
def init_weights(self, pretrained=None):
if isinstance(pretrained, str):
logger = 1
#load_checkpoint(self, pretrained, map_location='cpu', strict=False, logger=logger)
def reset_drop_path(self, drop_path_rate):
dpr = [x.item() for x in torch.linspace(0, drop_path_rate, sum(self.depths))]
cur = 0
for i in range(self.depths[0]):
self.block1[i].drop_path.drop_prob = dpr[cur + i]
cur += self.depths[0]
for i in range(self.depths[1]):
self.block2[i].drop_path.drop_prob = dpr[cur + i]
cur += self.depths[1]
for i in range(self.depths[2]):
self.block3[i].drop_path.drop_prob = dpr[cur + i]
cur += self.depths[2]
for i in range(self.depths[3]):
self.block4[i].drop_path.drop_prob = dpr[cur + i]
def freeze_patch_emb(self):
self.patch_embed1.requires_grad = False
@torch.jit.ignore
def no_weight_decay(self):
return {'pos_embed1', 'pos_embed2', 'pos_embed3', 'pos_embed4', 'cls_token'} # has pos_embed may be better
def get_classifier(self):
return self.head
def reset_classifier(self, num_classes, global_pool=''):
self.num_classes = num_classes
self.head = nn.Linear(self.embed_dim, num_classes) if num_classes > 0 else nn.Identity()
# def _get_pos_embed(self, pos_embed, patch_embed, H, W):
# if H * W == self.patch_embed1.num_patches:
# return pos_embed
# else:
# return F.interpolate(
# pos_embed.reshape(1, patch_embed.H, patch_embed.W, -1).permute(0, 3, 1, 2),
# size=(H, W), mode="bilinear").reshape(1, -1, H * W).permute(0, 2, 1)
def forward_features(self, x):
B = x.shape[0]
outs = []
# stage 1
x, H, W = self.patch_embed1(x)
for i, blk in enumerate(self.block1):
x = blk(x, H, W)
x = self.norm1(x)
x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
outs.append(x)
# stage 2
x, H, W = self.patch_embed2(x)
for i, blk in enumerate(self.block2):
x = blk(x, H, W)
x = self.norm2(x)
x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
outs.append(x)
# stage 3
x, H, W = self.patch_embed3(x)
for i, blk in enumerate(self.block3):
x = blk(x, H, W)
x = self.norm3(x)
x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
outs.append(x)
# stage 4
x, H, W = self.patch_embed4(x)
for i, blk in enumerate(self.block4):
x = blk(x, H, W)
x = self.norm4(x)
x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
outs.append(x)
return outs
# return x.mean(dim=1)
def forward(self, x):
x = self.forward_features(x)
# x = self.head(x)
return x
class DWConv(nn.Module):
def __init__(self, dim=768):
super(DWConv, self).__init__()
self.dwconv = nn.Conv2d(dim, dim, 3, 1, 1, bias=True, groups=dim)
def forward(self, x, H, W):
B, N, C = x.shape
x = x.transpose(1, 2).view(B, C, H, W)
x = self.dwconv(x)
x = x.flatten(2).transpose(1, 2)
return x
def _conv_filter(state_dict, patch_size=16):
""" convert patch embedding weight from manual patchify + linear proj to conv"""
out_dict = {}
for k, v in state_dict.items():
if 'patch_embed.proj.weight' in k:
v = v.reshape((v.shape[0], 3, patch_size, patch_size))
out_dict[k] = v
return out_dict
class pvt_v2_b0(PyramidVisionTransformerImpr):
def __init__(self, **kwargs):
super(pvt_v2_b0, self).__init__(
patch_size=4, embed_dims=[32, 64, 160, 256], num_heads=[1, 2, 5, 8], mlp_ratios=[8, 8, 4, 4],
qkv_bias=True, norm_layer=partial(nn.LayerNorm, eps=1e-6), depths=[2, 2, 2, 2], sr_ratios=[8, 4, 2, 1],
drop_rate=0.0, drop_path_rate=0.1)
class pvt_v2_b1(PyramidVisionTransformerImpr):
def __init__(self, **kwargs):
super(pvt_v2_b1, self).__init__(
patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[8, 8, 4, 4],
qkv_bias=True, norm_layer=partial(nn.LayerNorm, eps=1e-6), depths=[2, 2, 2, 2], sr_ratios=[8, 4, 2, 1],
drop_rate=0.0, drop_path_rate=0.1)
class pvt_v2_b2(PyramidVisionTransformerImpr):
def __init__(self, **kwargs):
super(pvt_v2_b2, self).__init__(
patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[8, 8, 4, 4],
qkv_bias=True, norm_layer=partial(nn.LayerNorm, eps=1e-6), depths=[3, 4, 6, 3], sr_ratios=[8, 4, 2, 1],
drop_rate=0.0, drop_path_rate=0.1)
class pvt_v2_b3(PyramidVisionTransformerImpr):
def __init__(self, **kwargs):
super(pvt_v2_b3, self).__init__(
patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[8, 8, 4, 4],
qkv_bias=True, norm_layer=partial(nn.LayerNorm, eps=1e-6), depths=[3, 4, 18, 3], sr_ratios=[8, 4, 2, 1],
drop_rate=0.0, drop_path_rate=0.1)
class pvt_v2_b4(PyramidVisionTransformerImpr):
def __init__(self, **kwargs):
super(pvt_v2_b4, self).__init__(
patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[8, 8, 4, 4],
qkv_bias=True, norm_layer=partial(nn.LayerNorm, eps=1e-6), depths=[3, 8, 27, 3], sr_ratios=[8, 4, 2, 1],
drop_rate=0.0, drop_path_rate=0.1)
class pvt_v2_b5(PyramidVisionTransformerImpr):
def __init__(self, **kwargs):
super(pvt_v2_b5, self).__init__(
patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
qkv_bias=True, norm_layer=partial(nn.LayerNorm, eps=1e-6), depths=[3, 6, 40, 3], sr_ratios=[8, 4, 2, 1],
drop_rate=0.0, drop_path_rate=0.1)
if __name__ == "__main__":
pretrained_path = "/afs/crc.nd.edu/user/y/ypeng4/Polyp-PVT_2/pvt_pth/pvt_v2_b2.pth"
model = pvt_v2_b5()
x = torch.rand((1, 3, 640, 640))
ys = model(x)
print(len(ys))
for y in ys:
print(y.shape)
四、添加方式
4.1 修改一
第一步还是建立文件，我们找到如下ultralytics/nn/modules文件夹下建立一个目录名字呢就是'Addmodules'文件夹(用群内的文件的话已经有了无需新建)！然后在其内部建立一个新的py文件将核心代码复制粘贴进去即可
4.2 修改二
第二步我们在该目录下创建一个新的py文件名字为'init.py'(用群内的文件的话已经有了无需新建)，然后在其内部导入我们的检测头如下图所示。
4.3 修改三
第三步我门中到如下文件'ultralytics/nn/tasks.py'进行导入和注册我们的模块(用群内的文件的话已经有了无需重新导入直接开始第四步即可)！
从今天开始以后的教程就都统一成这个样子了，因为我默认大家用了我群内的文件来进行修改！！
4.4 修改四
添加如下两行代码！！！
4.5 修改五
找到七百多行大概把具体看图片，按照图片来修改就行，添加红框内的部分，注意没有()只是函数名。
elif m in {自行添加对应的模型即可，下面都是一样的}:
m = m(*args)
c2 = m.width_list # 返回通道列表
backbone = True
4.6 修改六
下面的两个红框内都是需要改动的。
if isinstance(c2, list):
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 backbone else i, f, t # attach index, 'from' index, type
4.7 修改七
如下的也需要修改，全部按照我的来。
代码如下把原先的代码替换了即可。
if verbose:
LOGGER.info(f'{i:>3}{str(f):>20}{n_:>3}{m.np:10.0f} {t:<45}{str(args):<30}') # print
save.extend(x % (i + 4 if 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)
if len(c2) != 5:
ch.insert(0, 0)
else:
ch.append(c2)
4.8 修改八
修改七和前面的都不太一样，需要修改前向传播中的一个部分， 已经离开了parse_model方法了。
可以在图片中开代码行数，没有离开task.py文件都是同一个文件。 同时这个部分有好几个前向传播都很相似，大家不要看错了，是70多行左右的！！！，同时我后面提供了代码，大家直接复制粘贴即可，有时间我针对这里会出一个视频。
代码如下->
def _predict_once(self, x, profile=False, visualize=False):
"""
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.
Returns:
(torch.Tensor): The last output of the model.
"""
y, dt = [], [] # outputs
for m in 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)
if len(x) != 5: # 0 - 5
x.insert(0, None)
for index, i in enumerate(x):
if index in self.save:
y.append(i)
else:
y.append(None)
x = x[-1] # 最后一个输出传给下一层
else:
x = m(x) # run
y.append(x if m.i in self.save else None) # save output
if visualize:
feature_visualization(x, m.type, m.i, save_dir=visualize)
return x
到这里就完成了修改部分，但是这里面细节很多，大家千万要注意不要替换多余的代码，导致报错，也不要拉下任何一部，都会导致运行失败，而且报错很难排查！！！很难排查！！！
注意！！！ 额外的修改！
关注我的其实都知道，我大部分的修改都是一样的，这个网络需要额外的修改一步，就是s一个参数，将下面的s改为640！！！即可完美运行！！
打印计算量问题解决方案
我们找到如下文件'ultralytics/utils/torch_utils.py'按照如下的图片进行修改，否则容易打印不出来计算量。
注意事项！！！
如果大家在验证的时候报错形状不匹配的错误可以固定验证集的图片尺寸，方法如下 ->
找到下面这个文件ultralytics/models/yolo/detect/train.py然后其中有一个类是DetectionTrainer class中的build_dataset函数中的一个参数rect=mode == 'val'改为rect=False
五、UNetV2的yaml文件
5.1 UNetV2的yaml文件
复制如下yaml文件进行运行！！！
# 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, pvt_v2_b0, []] # 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)
5.2 训练文件的代码
可以复制我的运行文件进行运行。
import warnings
warnings.filterwarnings('ignore')
from ultralytics import YOLO
if __name__ == '__main__':
model = YOLO("替换你的yaml文件地址")
model.load('yolov8n.pt')
model.train(data=r'你的数据集的地址',
cache=False,
imgsz=640,
epochs=150,
batch=4,
close_mosaic=0,
workers=0,
device=0,
optimizer='SGD'
amp=False,
)
六、成功运行记录
下面是成功运行的截图，已经完成了有1个epochs的训练，图片太大截不全第2个epochs了。
七、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**，**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~
