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改进YOLOv7系列:28.YOLOv7 结合 Swin Transformer V2结构,Swin Transformer V2:通向视觉大模型之路

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YOLOAir:助力YOLO论文改进 、 不同数据集涨点、创新点改进

YOLOAir项目:基于 YOLOv7 代码框架,结合不同模块来构建不同的YOLO目标检测模型。
本项目包含大量的改进方式,降低改进难度,改进点包含Backbone
Neck
Head
注意力机制
IoU损失函数
NMS
Loss计算方式
自注意力机制
数据增强部分
激活函数
等部分,详情可以关注 YOLOAir
的说明文档。
同时附带各种改进点原理及对应的代码改进方式教程
,用户可根据自身情况快速排列组合,在不同的数据集上实验, 应用组合写论文, 创造自己的毕业项目!

对于这块有疑问的,可以在评论区提出,或者私信CSDN。

 

本篇是《YOLOv7结合Swin Transformer V2结构》的修改 演示

 

使用YOLOv7网络作为示范,可以加入到 YOLOv7、YOLOX、YOLOR、YOLOv4、Scaled_YOLOv4、YOLOv3等一系列YOLO算法模块

 

文章目录

YOLOv7结合Swin Transformer-V2 演示教程

Swin Transformer论文

 

 

 

 

 

该论文作者提出了缩放 Swin Transformer 的技术 多达 30 亿个参数,使其能够使用多达 1,536 个图像进行训练1,536 分辨率。通过扩大容量和分辨率,Swin Transformer 在四个具有代表性的视觉基准上创造了新记录:ImageNet-V2 图像分类的84.0% top-1 准确率,COCO 对象检测的63.1 / 54.4 box / mask mAP,ADE20K 语义分割的59.9 mIoU,和86.8%Kinetics-400 视频动作分类的前 1 准确率。我们的技术通常适用于扩大视觉模型,但尚未像 NLP 语言模型那样被广泛探索,部分原因是在训练和应用方面存在以下困难:1)视觉模型经常面临大规模的不稳定性问题和 2)许多下游视觉任务需要高分辨率图像或窗口,目前尚不清楚如何有效地将低分辨率预训练的模型转移到更高分辨率的模型。当图像分辨率很高时,GPU 内存消耗也是一个问题。为了解决这些问题,我们提出了几种技术,并通过使用 Swin Transformer 作为案例研究来说明:1)后归一化技术和缩放余弦注意方法,以提高大型视觉模型的稳定性;2) 一种对数间隔的连续位置偏差技术,可有效地将在低分辨率图像和窗口上预训练的模型转移到其更高分辨率的对应物上。此外,我们分享了我们的关键实现细节,这些细节可以显着节省 GPU 内存消耗,从而使使用常规 GPU 训练大型视觉模型变得可行。使用这些技术和自我监督的预训练,我们成功训练了一个强大的 30 亿个 Swin Transformer 模型,并有效地将其转移到涉及高分辨率图像或窗口的各种视觉任务中,在各种的基准。代码将在 我们分享了我们的关键实现细节,这些细节可以显着节省 GPU 内存消耗,从而使使用常规 GPU 训练大型视觉模型变得可行。使用这些技术和自我监督的预训练,我们成功训练了一个强大的 30 亿个 Swin Transformer 模型,并有效地将其转移到涉及高分辨率图像或窗口的各种视觉任务中,在各种的基准。代码将在 我们分享了我们的关键实现细节,这些细节可以显着节省 GPU 内存消耗,从而使使用常规 GPU 训练大型视觉模型变得可行。使用这些技术和自我监督的预训练,我们成功训练了一个强大的 30 亿个 Swin Transformer 模型,并有效地将其转移到涉及高分辨率图像或窗口的各种视觉任务中,在各种的基准。代码将在 我们成功训练了一个强大的 30 亿个 Swin Transformer 模型,并将其有效地转移到涉及高分辨率图像或窗口的各种视觉任务中,在各种基准测试中达到了最先进的精度。代码将在 我们成功训练了一个强大的 30 亿个 Swin Transformer 模型,并将其有效地转移到涉及高分辨率图像或窗口的各种视觉任务中,在各种基准测试中达到了最先进的精度。

 

YOLOv7结合Swin Transformer-V2 演示教程

 

YOLOv7的yaml配置文件

 

首先增加以下yolov7_swin_transfomrer.yaml文件

 

# YOLOv7 , GPL-3.0 license
# parameters
nc: 80  # number of classes
depth_multiple: 0.33  # model depth multiple
width_multiple: 1.0  # layer channel multiple
# anchors
anchors:
  - [12,16, 19,36, 40,28]  # P3/8
  - [36,75, 76,55, 72,146]  # P4/16
  - [142,110, 192,243, 459,401]  # P5/32
# yolov7 backbone by yoloair
backbone:
  # [from, number, module, args]
  [[-1, 1, Conv, [32, 3, 1]],  # 0
   [-1, 1, Conv, [64, 3, 2]],  # 1-P1/2
   [-1, 1, Conv, [64, 3, 1]],
   [-1, 1, Conv, [128, 3, 2]],  # 3-P2/4 
   [-1, 1, SwinV2_CSPB, [128, 128]], 
   [-1, 1, Conv, [256, 3, 2]], 
   [-1, 1, MP, []],
   [-1, 1, Conv, [128, 1, 1]],
   [-3, 1, Conv, [128, 1, 1]],
   [-1, 1, Conv, [128, 3, 2]],
   [[-1, -3], 1, Concat, [1]],  # 16-P3/8
   [-1, 1, Conv, [128, 1, 1]],
   [-2, 1, Conv, [128, 1, 1]],
   [-1, 1, Conv, [128, 3, 1]],
   [-1, 1, Conv, [128, 3, 1]],
   [-1, 1, Conv, [128, 3, 1]],
   [-1, 1, Conv, [128, 3, 1]],
   [[-1, -3, -5, -6], 1, Concat, [1]],
   [-1, 1, Conv, [512, 1, 1]],
   [-1, 1, MP, []],
   [-1, 1, Conv, [256, 1, 1]],
   [-3, 1, Conv, [256, 1, 1]],
   [-1, 1, Conv, [256, 3, 2]],
   [[-1, -3], 1, Concat, [1]],
   [-1, 1, Conv, [256, 1, 1]],
   [-2, 1, Conv, [256, 1, 1]],
   [-1, 1, Conv, [256, 3, 1]],
   [-1, 1, Conv, [256, 3, 1]],
   [-1, 1, Conv, [256, 3, 1]],
   [-1, 1, Conv, [256, 3, 1]],
   [[-1, -3, -5, -6], 1, Concat, [1]],
   [-1, 1, Conv, [1024, 1, 1]],          
   [-1, 1, MP, []],
   [-1, 1, Conv, [512, 1, 1]],
   [-3, 1, Conv, [512, 1, 1]],
   [-1, 1, Conv, [512, 3, 2]],
   [[-1, -3], 1, Concat, [1]],
   [-1, 1, SwinV2_CSPB, [1024, 1024]],
   [-1, 1, Conv, [256, 3, 1]],
  ]
# yolov7 head by yoloair
head:
  [[-1, 1, SPPCSPC, [512]],
   [-1, 1, Conv, [256, 1, 1]],
   [-1, 1, nn.Upsample, [None, 2, 'nearest']],
   [31, 1, Conv, [256, 1, 1]],
   [[-1, -2], 1, Concat, [1]],
   [-1, 1, C3STR, [128]],
   [-1, 1, Conv, [128, 1, 1]],
   [-1, 1, nn.Upsample, [None, 2, 'nearest']],
   [18, 1, Conv, [128, 1, 1]],
   [[-1, -2], 1, Concat, [1]],
   [-1, 1, C3STR, [128]],
   [-1, 1, MP, []],
   [-1, 1, Conv, [128, 1, 1]],
   [-3, 1, Conv, [128, 1, 1]],
   [-1, 1, Conv, [128, 3, 2]],
   [[-1, -3, 44], 1, Concat, [1]],
   [-1, 1, C3STR, [256]], 
   [-1, 1, MP, []],
   [-1, 1, Conv, [256, 1, 1]],
   [-3, 1, Conv, [256, 1, 1]],
   [-1, 1, Conv, [256, 3, 2]], 
   [[-1, -3, 39], 1, Concat, [1]],
   [-1, 3, C3STR, [512]],
# 检测头 -----------------------------
   [49, 1, RepConv, [256, 3, 1]],
   [55, 1, RepConv, [512, 3, 1]],
   [61, 1, RepConv, [1024, 3, 1]],
   [[62,63,64], 1, IDetect, [nc, anchors]],   # Detect(P3, P4, P5)
  ]

 

common.py配置

 

在./models/common.py文件中增加以下模块,直接复制即可

 

class WindowAttention_v2(nn.Module):
    def __init__(self, dim, window_size, num_heads, qkv_bias=True, attn_drop=0., proj_drop=0.,
                 pretrained_window_size=[0, 0]):
        super().__init__()
        self.dim = dim
        self.window_size = window_size  # Wh, Ww
        self.pretrained_window_size = pretrained_window_size
        self.num_heads = num_heads
        self.logit_scale = nn.Parameter(torch.log(10 * torch.ones((num_heads, 1, 1))), requires_grad=True)
        # mlp to generate continuous relative position bias
        self.cpb_mlp = nn.Sequential(nn.Linear(2, 512, bias=True),
                                     nn.ReLU(inplace=True),
                                     nn.Linear(512, num_heads, bias=False))
        # get relative_coords_table
        relative_coords_h = torch.arange(-(self.window_size[0] - 1), self.window_size[0], dtype=torch.float32)
        relative_coords_w = torch.arange(-(self.window_size[1] - 1), self.window_size[1], dtype=torch.float32)
        relative_coords_table = torch.stack(
            torch.meshgrid([relative_coords_h,
                            relative_coords_w])).permute(1, 2, 0).contiguous().unsqueeze(0)  # 1, 2*Wh-1, 2*Ww-1, 2
        if pretrained_window_size[0] > 0:
            relative_coords_table[:, :, :, 0] /= (pretrained_window_size[0] - 1)
            relative_coords_table[:, :, :, 1] /= (pretrained_window_size[1] - 1)
        else:
            relative_coords_table[:, :, :, 0] /= (self.window_size[0] - 1)
            relative_coords_table[:, :, :, 1] /= (self.window_size[1] - 1)
        relative_coords_table *= 8  # normalize to -8, 8
        relative_coords_table = torch.sign(relative_coords_table) * torch.log2(
            torch.abs(relative_coords_table) + 1.0) / np.log2(8)
        self.register_buffer("relative_coords_table", relative_coords_table)
        # get pair-wise relative position index for each token inside the window
        coords_h = torch.arange(self.window_size[0])
        coords_w = torch.arange(self.window_size[1])
        coords = torch.stack(torch.meshgrid([coords_h, coords_w]))  # 2, Wh, Ww
        coords_flatten = torch.flatten(coords, 1)  # 2, Wh*Ww
        relative_coords = coords_flatten[:, :, None] - coords_flatten[:, None, :]  # 2, Wh*Ww, Wh*Ww
        relative_coords = relative_coords.permute(1, 2, 0).contiguous()  # Wh*Ww, Wh*Ww, 2
        relative_coords[:, :, 0] += self.window_size[0] - 1  # shift to start from 0
        relative_coords[:, :, 1] += self.window_size[1] - 1
        relative_coords[:, :, 0] *= 2 * self.window_size[1] - 1
        relative_position_index = relative_coords.sum(-1)  # Wh*Ww, Wh*Ww
        self.register_buffer("relative_position_index", relative_position_index)
        self.qkv = nn.Linear(dim, dim * 3, bias=False)
        if qkv_bias:
            self.q_bias = nn.Parameter(torch.zeros(dim))
            self.v_bias = nn.Parameter(torch.zeros(dim))
        else:
            self.q_bias = None
            self.v_bias = None
        self.attn_drop = nn.Dropout(attn_drop)
        self.proj = nn.Linear(dim, dim)
        self.proj_drop = nn.Dropout(proj_drop)
        self.softmax = nn.Softmax(dim=-1)
    def forward(self, x, mask=None):
        
        B_, N, C = x.shape
        qkv_bias = None
        if self.q_bias is not None:
            qkv_bias = torch.cat((self.q_bias, torch.zeros_like(self.v_bias, requires_grad=False), self.v_bias))
        qkv = F.linear(input=x, weight=self.qkv.weight, bias=qkv_bias)
        qkv = qkv.reshape(B_, N, 3, self.num_heads, -1).permute(2, 0, 3, 1, 4)
        q, k, v = qkv[0], qkv[1], qkv[2]  # make torchscript happy (cannot use tensor as tuple)
        # cosine attention
        attn = (F.normalize(q, dim=-1) @ F.normalize(k, dim=-1).transpose(-2, -1))
        logit_scale = torch.clamp(self.logit_scale, max=torch.log(torch.tensor(1. / 0.01))).exp()
        attn = attn * logit_scale
        relative_position_bias_table = self.cpb_mlp(self.relative_coords_table).view(-1, self.num_heads)
        relative_position_bias = relative_position_bias_table[self.relative_position_index.view(-1)].view(
            self.window_size[0] * self.window_size[1], self.window_size[0] * self.window_size[1], -1)  # Wh*Ww,Wh*Ww,nH
        relative_position_bias = relative_position_bias.permute(2, 0, 1).contiguous()  # nH, Wh*Ww, Wh*Ww
        relative_position_bias = 16 * torch.sigmoid(relative_position_bias)
        attn = attn + relative_position_bias.unsqueeze(0)
        if mask is not None:
            nW = mask.shape[0]
            attn = attn.view(B_ // nW, nW, self.num_heads, N, N) + mask.unsqueeze(1).unsqueeze(0)
            attn = attn.view(-1, self.num_heads, N, N)
            attn = self.softmax(attn)
        else:
            attn = self.softmax(attn)
        attn = self.attn_drop(attn)
        try:
            x = (attn @ v).transpose(1, 2).reshape(B_, N, C)
        except:
            x = (attn.half() @ v).transpose(1, 2).reshape(B_, N, C)
            
        x = self.proj(x)
        x = self.proj_drop(x)
        return x
    def extra_repr(self) -> str:
        return f'dim={
   self.dim}, window_size={
   self.window_size}, ' \
               f'pretrained_window_size={
   self.pretrained_window_size}, num_heads={
   self.num_heads}'
    def flops(self, N):
        # calculate flops for 1 window with token length of N
        flops = 0
        # qkv = self.qkv(x)
        flops += N * self.dim * 3 * self.dim
        # attn = (q @ k.transpose(-2, -1))
        flops += self.num_heads * N * (self.dim // self.num_heads) * N
        #  x = (attn @ v)
        flops += self.num_heads * N * N * (self.dim // self.num_heads)
        # x = self.proj(x)
        flops += N * self.dim * self.dim
        return flops
    
class Mlp_v2(nn.Module):
    def __init__(self, in_features, hidden_features=None, out_features=None, act_layer=nn.SiLU, 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.act = act_layer()
        self.fc2 = nn.Linear(hidden_features, out_features)
        self.drop = nn.Dropout(drop)
    def forward(self, x):
        x = self.fc1(x)
        x = self.act(x)
        x = self.drop(x)
        x = self.fc2(x)
        x = self.drop(x)
        return x
# add 2 functions
class SwinTransformerLayer_v2(nn.Module):
    def __init__(self, dim, num_heads, window_size=7, shift_size=0,
                 mlp_ratio=4., qkv_bias=True, drop=0., attn_drop=0., drop_path=0.,
                 act_layer=nn.SiLU, norm_layer=nn.LayerNorm, pretrained_window_size=0):
        super().__init__()
        self.dim = dim
        #self.input_resolution = input_resolution
        self.num_heads = num_heads
        self.window_size = window_size
        self.shift_size = shift_size
        self.mlp_ratio = mlp_ratio
        #if min(self.input_resolution) <= self.window_size:
        #    # if window size is larger than input resolution, we don't partition windows
        #    self.shift_size = 0
        #    self.window_size = min(self.input_resolution)
        assert 0 <= self.shift_size < self.window_size, "shift_size must in 0-window_size"
        self.norm1 = norm_layer(dim)
        self.attn = WindowAttention_v2(
            dim, window_size=(self.window_size, self.window_size), num_heads=num_heads,
            qkv_bias=qkv_bias, attn_drop=attn_drop, proj_drop=drop,
            pretrained_window_size=(pretrained_window_size, pretrained_window_size))
        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_v2(in_features=dim, hidden_features=mlp_hidden_dim, act_layer=act_layer, drop=drop)
    def create_mask(self, H, W):
        # calculate attention mask for SW-MSA
        img_mask = torch.zeros((1, H, W, 1))  # 1 H W 1
        h_slices = (slice(0, -self.window_size),
                    slice(-self.window_size, -self.shift_size),
                    slice(-self.shift_size, None))
        w_slices = (slice(0, -self.window_size),
                    slice(-self.window_size, -self.shift_size),
                    slice(-self.shift_size, None))
        cnt = 0
        for h in h_slices:
            for w in w_slices:
                img_mask[:, h, w, :] = cnt
                cnt += 1
        mask_windows = window_partition(img_mask, self.window_size)  # nW, window_size, window_size, 1
        mask_windows = mask_windows.view(-1, self.window_size * self.window_size)
        attn_mask = mask_windows.unsqueeze(1) - mask_windows.unsqueeze(2)
        attn_mask = attn_mask.masked_fill(attn_mask != 0, float(-100.0)).masked_fill(attn_mask == 0, float(0.0))
        return attn_mask
    def forward(self, x):
        # reshape x[b c h w] to x[b l c]
        _, _, H_, W_ = x.shape
        Padding = False
        if min(H_, W_) < self.window_size or H_ % self.window_size!=0 or W_ % self.window_size!=0:
            Padding = True
            # print(f'img_size {min(H_, W_)} is less than (or not divided by) window_size {self.window_size}, Padding.')
            pad_r = (self.window_size - W_ % self.window_size) % self.window_size
            pad_b = (self.window_size - H_ % self.window_size) % self.window_size
            x = F.pad(x, (0, pad_r, 0, pad_b))
        # print('2', x.shape)
        B, C, H, W = x.shape
        L = H * W
        x = x.permute(0, 2, 3, 1).contiguous().view(B, L, C)  # b, L, c
        # create mask from init to forward
        if self.shift_size > 0:
            attn_mask = self.create_mask(H, W).to(x.device)
        else:
            attn_mask = None
        shortcut = x
        x = x.view(B, H, W, C)
        # cyclic shift
        if self.shift_size > 0:
            shifted_x = torch.roll(x, shifts=(-self.shift_size, -self.shift_size), dims=(1, 2))
        else:
            shifted_x = x
        # partition windows
        x_windows = window_partition_v2(shifted_x, self.window_size)  # nW*B, window_size, window_size, C
        x_windows = x_windows.view(-1, self.window_size * self.window_size, C)  # nW*B, window_size*window_size, C
        # W-MSA/SW-MSA
        attn_windows = self.attn(x_windows, mask=attn_mask)  # nW*B, window_size*window_size, C
        # merge windows
        attn_windows = attn_windows.view(-1, self.window_size, self.window_size, C)
        shifted_x = window_reverse_v2(attn_windows, self.window_size, H, W)  # B H' W' C
        # reverse cyclic shift
        if self.shift_size > 0:
            x = torch.roll(shifted_x, shifts=(self.shift_size, self.shift_size), dims=(1, 2))
        else:
            x = shifted_x
        x = x.view(B, H * W, C)
        x = shortcut + self.drop_path(self.norm1(x))
        # FFN
        x = x + self.drop_path(self.norm2(self.mlp(x)))
        x = x.permute(0, 2, 1).contiguous().view(-1, C, H, W)  # b c h w
        
        if Padding:
            x = x[:, :, :H_, :W_]  # reverse padding
        return x
    def extra_repr(self) -> str:
        return f"dim={
   self.dim}, input_resolution={
   self.input_resolution}, num_heads={
   self.num_heads}, " \
               f"window_size={
   self.window_size}, shift_size={
   self.shift_size}, mlp_ratio={
   self.mlp_ratio}"
    def flops(self):
        flops = 0
        H, W = self.input_resolution
        # norm1
        flops += self.dim * H * W
        # W-MSA/SW-MSA
        nW = H * W / self.window_size / self.window_size
        flops += nW * self.attn.flops(self.window_size * self.window_size)
        # mlp
        flops += 2 * H * W * self.dim * self.dim * self.mlp_ratio
        # norm2
        flops += self.dim * H * W
        return flops
class SwinTransformer2Block(nn.Module):
    def __init__(self, c1, c2, num_heads, num_layers, window_size=7):
        super().__init__()
        self.conv = None
        if c1 != c2:
            self.conv = Conv(c1, c2)
        # remove input_resolution
        self.blocks = nn.Sequential(*[SwinTransformerLayer_v2(dim=c2, num_heads=num_heads, window_size=window_size,
                                 shift_size=0 if (i % 2 == 0) else window_size // 2) for i in range(num_layers)])
    def forward(self, x):
        if self.conv is not None:
            x = self.conv(x)
        x = self.blocks(x)
        return x
class SwinV2_CSPB(nn.Module):
    # CSP Bottleneck https://github.com/WongKinYiu/CrossStagePartialNetworks
    def __init__(self, c1, c2, n=1, shortcut=False, g=1, e=0.5):  # ch_in, ch_out, number, shortcut, groups, expansion
        super(SwinV2_CSPB, self).__init__()
        c_ = int(c2)  # hidden channels
        self.cv1 = Conv(c1, c_, 1, 1)
        self.cv2 = Conv(c_, c_, 1, 1)
        self.cv3 = Conv(2 * c_, c2, 1, 1)
        num_heads = c_ // 32
        self.m = SwinTransformer2Block(c_, c_, num_heads, n)
        #self.m = nn.Sequential(*[Bottleneck(c_, c_, shortcut, g, e=1.0) for _ in range(n)])
    def forward(self, x):
        x1 = self.cv1(x)
        y1 = self.m(x1)
        y2 = self.cv2(x1)
        return self.cv3(torch.cat((y1, y2), dim=1))

 

训练yolov7_swin_transfomrer-V2模型

 

python train.py --cfg yolov7_swin_transfomrer-V2.yaml

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