计算机视觉篇---图像分类实战+理论讲解(6)Mobilenet

Mobilenetv

创新点

  1. 在于DW卷积与PW卷积
    传统卷积是224-224-3 卷积核 5-5-3-K 输出为 117-117-K
    DW卷积 224-224-3 卷积核 5-5-3 输出为 117-117-3 输入等于输出的通道数
    PW卷积 224-224-3 卷积核 1-1-3-k 输出为 117-117-k
    Mobilenet卷积:3x3 Depthwise Conv+BN+ReLU 和 1x1 Pointwise Conv+BN+ReLU
    请添加图片描述
  2. 使用快速通道残差,先升维再降维
    请添加图片描述
  3. V2 激活函数 relu6
  4. V3 引入SE结构,使用新的H SWISH 激活函数 文章中最后一层模块使用线性激活函数
```bash
from torch import nn
import torch
def _make_divisible(ch,divisor=8,min_ch=None):
    if min_ch is None:
        min_ch=divisor
    new_ch=max(min_ch,int(ch+divisor/2)//divisor*divisor)
    if new_ch<0.9*ch
        new_ch+=divisor
    return new_ch


class ConvBNReLU(nn.Sequential):
    def__init__(self,in_channel,out_channel,kernel_size=3,stride=1,group=1):
    padding=(kernel_size-1)//2
    super(ConvBNReLU, self).__init__(
    nn.Conv2d(in_channel,out_channel,kernel_size,stride,padding,groups=groups,bias=False),
    nn.BatchNormal2d(out_channel),
    nn.ReLU6(inplace=True)
class InvertedResidual(nn.Module):
    def __init__(self,in_channel,out_channel,stride,expand-ratio):
        super(InvertedResidual,self).__init__()
        hidden_channel=in_channel*expand_ratio
        self.use_shortcut=stride==1 and inchannel==out_channel
        layer=[]
        if expand_ratio!=1:
        #如果有扩大因子那么就使用1*1分离卷积
            layers.append(ConvBNReLU(in_channel,hidden_channel,kernel_size=1))
            layers.extend([ConvBNReLU(hidden_channel,hidden_channel,stride=stride,groups=hidden_channels),
            #3*3卷积核卷积
            nn.Conv2d(hidden_channel,out_channel,kernel_size=1,bias=False),
            nn.BatchNorm2d(out_channel),])
            #没有bn层
            self.conv=nn.Sequential(*layers)
        def forward(self,x):
            if self.use_shortcut:
                return x+self.conv(x)
            else 
                return self.conv(x)
class MobileNetV2(nn.Module):
    def__init__(self,num_classes=1000,alpha=1.0,round_nearest=8):
       super(MobileNetV2,self).__init__()
       block=InvertedResidual
       input_channel=_make_divisible(32*alpha,round_nearest)
       last_channel=_make_divisible(1280*alpha,round_nearest)
       inverted_residual_setting=[
       [1,16,1,1],
       [6,24,2,2],
       #第一个参数是扩大因子 第二个是层数输出的通道数 第三个是这样的模块个数 第四个是stride
       [6, 32, 3, 2],
       [6, 64, 4, 2],
       [6, 96, 3, 1],
       [6, 160, 3, 2],
       [6, 320, 1, 1],
        ]
       features=[]
       features.append(ConvBNReLU(3,input_channel,stride=2))
       for t,c,n,s in inverted_residual_setting:
           output_channel=_make_divisible(c*alpha,round_nearest)
           for i in range(n):
               stride=s if i=i==0 else 1
               features.append(block(input_channel,output_channel,stride,expand_radio=t)
               input_channel=output_channel
       features.append(ConvBNReLU(input_channel,last_channel,1))
       self.features=nn.Sequential(*features)
       self.avgpool=nn.AdaptiveAvgPool2d((1,1))
       self.classifier=nn.Sequential(
       nn.Dropout(0.2)
       nn.Linear(last_channel,num_classes)

)
        for m in self.modules():
            if isinstance(m,nn.Conv2d):
                nn.init.kaiming_normal_(m.weight,mode='fan_out)
                if m.bias is not None:
                    nn.init.zeros_(m.bias)
            elif isinstance(m,nn.BatchNorm2d):
                nn.init.ones_(m.weight)
                nn.init.zeros_(m.bias)
            elif isinstance(m,nn.Linear):
               nn.init.normal_(m.weight,0,0.01)
               nn.init.zeros_(m.bias)
   def forward(self,x):
       x=self.features(x)
       x=self.avgpool(x)
       x=torch.flatten(x.1)
       x=self.classifier(x)
       return x

训练

import os 
import json
import torch
import torch.nn as nn
import torch.optim as optim
import torchvision import transforms, datasets
import tqdm import tqdm

from model_v2 import MobileNetV2

def mian():
    device=torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
    print("using {} device.".format(device))
    batch_size=64
    epochs=5
    data_transform={
    "train":transforms.Compose([transforms.RandomResizeCrop(224),
    transforms.RandomHorizontalFlip(),
    transforms.ToTensor(),
    transforms.Normalize([0.5,0.5,0.5].[0.5,0.5,0.5]),
    "val":transforms.Compose([transforms.Resize(256),
    transforms.CenterCrop(224),
    transforms.ToTensor(),
    transforms.Normalize([0.5,0.5,0.5],[0.5,0.5,0.5])])
    }
    data_root=os.path.abspath(os.path.join(os.getcwd(),"../.."))
    image_path=os.path.join(data_root,"data_set","flower_data")
    assert os.path.exists(image_path),"{} path does not exist.".format(image_path)
    train_dataset=datasets.ImageFolder(root=os.path.join(imge_path,"train",transform=data_transform["train"])
    train_num=len(train_dataset)
    flower_list=train_dataset.class_to_idx
    cla_dict=dict((val,key) for key,val in flower_list.items())
    json_str=json.dump(cla_dict,indent=4)
    with open('class_indices.json','w') as json_file:
        fson_file.write(json_str)
    nw=min([os.cpu_count(),batch_size if batch_size>1 else 0,8])
    print("using {} dataloader workers every process'.format(nw))
    train_loader=torch.utils.data.DataLoader(train_dataset,batch_size=batch_size=batch_size,shuffle=True,num_workers=nw)
    validate_dataset=datasets.ImageFolder(root=os.path.join(image_path,"val"),transform=data_transform["val"])
    val_num=len(validate_dataset)
    validate_loader=torch.util.data.DataLoader(validate_dataset.batch_size=batch_size,shuffle=False,num_workers=nw)
    net=MobileNetV2(num_classes=5)
    model_weight_path="./mobilenet_v2.pth"
    assert os.path.exists(model_weight_path),"file {} dose not exist.".format(model_weight_path)
    pre_weights=torch.load(model_weight_path,map_location=device)
    pre_dict={k:v for k,v in pre_weights.items() if net.state_dict()[k].numel()==v.numel()}
    missing_key,unexpected_keys=net.load_state_dict(pre_dict,strict=False)
    for param in net.features.parameters():
        param.requires_grad=False
    net.to(device)
    loss_function=nn.CrossEntropyLoss()
    params=[p for p in net.parameters() if p.requires_grad]
    optimizer=optim.Adam(params,lr=0.0001)
    best_acc=0.0
    save_path='./MobileNetV2.pth'
    train_steps=len(train_loader)
    for epoch in range(epochs):
        net.train()
        running_loss=0.0
        train_bar=tpdm(train_loader)
        for step,data in enumerate(train_bar):
            images,labels=data
            optimizer.zero_grad()
            logits=net(image.to(device))
            loss=loss_function(logits,label.to(device))
            loss.backward()
            optimizer.step()
            running_loss+=loss.item()
            train_bar.desc="trian epoch[{}/{}] loss:{:.3f}".format(epoch+1,epoches,loss)
        net.eval()
        acc=0.0
        with torch.no_grad():
            val_bar=tqdm(validate_loader)
            for val_data in val_bar:
                val_images,val_labels=val_data
                outputs=net(image.to(device))
                predict_y=torch.max(outputs,dim=1)[1]
                acc+=torch.eq(predict_y,val_labels.to(device)).sum().item()
                val_bar.desc="valid epoch[{}/{}]".format(epoch+1,epochs)
        val_accurate=acc/val_num
        print('[epoch %d] train_loss: %.3f val_accuracy: %.3f' %(epoch+1,running_loss/train_steps,val_accurate))
        if val_accurate>best_acc:
            best_acc=val_accurate
            torch.save(net.state_dict(),save_path)
    print('Finished Training')

if __name__=='__main__':
    main()
    



预测

import os
import json
import torch
from PIL import Image
from torchvision import transforms
import matplotlib.pyplot as plt
from model_v2 import MobileNetV2
def main():
    device=torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
    data_transform=transforms.Compose(
    [transforms.Resize(224),
    transforms.CenterCrop(224),
    transforms.ToTensor(),
    transforms.Normalize([0.5,0.5,0.5],[0.5,0.5,0.5])
    ])
    img_path="../tulip.jpg"
    assert os.path.exists(img_path),"file:'{}' dose not exist.".format(img_path)
    img=Image.open(img_path)
    plt.imshow(img)
    img=data_transform(img)
    img=torch.unsqueeze(img,dim=0)
    json_file=open(json_path,"r")
    class_indict=json.load(json_file)
    model=ModileNetV2(num_classes=5).to(device)
    model_weight_path="./MobileNetV2.pth"
    model.load_state_dict(torch.load(model_weight_path,map_location=device))
    model.eval()
    with torch.no_grad():
        output=torch.squeeze(model(img.to(device))).cpu()
        predict=torch.softmax(output,dim=0)
        predict_cla=torch.argmax(predict).numpy()
    print_res="class:{} prob:{:.3}".format(class_indict[str(predict_cal)]  ,predict[predict_cla].numpy() 
    plt.title(print_res)
    print(print_res)
    plt.show()
if__name__=='__main__':
     main()



mobilenetv3
在这里插入图片描述

from typing import Callable,List,Optional
import torch
from torch import nn,Tensor
from torch.nn import function as F
from funtools import partial

def _make_divisible(ch,divisior=8,min_ch=None):
#使得channel 保持在8的倍数,更好的训练
    if min_ch is None:
        min_ch=divisor
    new_ch=max(min_ch,int(ch+divisor/2)//divisor*divisor)
    if new_ch<0.9 *ch
        new_ch+=divisor
    return new_ch
class ConvBNActivation(nn.Sequential):
    def __init__(self,in_planes:int,out_planes:int=3,stride:int=1,group:int=1,norm_layer:Optional[Callable[...,nn.Module]]=None,activation_layer:Optional[Callable[...,nn.Module]]=None):#后两个是none
    if norm_layer is None:
        norm_layer=nn.BatchNorm2d
    if activation_layer is None:
        activeation_layer=nn.ReLU6
    super(ConvBNActivation,self).__init__(nn.Conv2d(in_channels=in_planes,out_channels=out_planes,kernel_size=kernel_size,stride=stride,padding=padding,groups=groups,bias=Flase), #group的使用是为了DW层
    norm_layer(out_planes),
    activation_layers(inplace=True))
    #Mobilenetv3中的卷积层,带BN 与特殊激活函数的卷积层
class SqueezeExcitation(nn.Module):
#SE 模块 首先降维,默认参数是维度减少4倍,SE模块是两个全连接层,首先降维,之后升到与输入一样的维度,根据输出的重要程度与输入相乘得到输出
    def __init__(self,input_c:int,squeeze_factor:int =4):
        super(SqueezeExcitation,self).__init__()
        squeeze_c=_make_divisible(input_c//squeeze_factor,8)
        self.fc1=nn.Conv2d(input_c,squeeze_c,1)
        self.fc2=nn.Conv2d(squeeze_c,input_c,1)
    def forward(self,x:Tensor)->Tensor:
        scale=F.adaptive_avg_pool2d(x,output_size=(1,1))
        scale=self.fc1(scale)
        scale=F.relu(scale,inplace=True)
        scale=self.fc2(scale)
        scale=F.hardsigmoid(scale,inpale=True)
           return scale*x  #重要程度与原输入相乘
           #SE并非是一个并行模块而是一个串行模块
class InvertedResidualConfig:
#倒残差 se模块 残差就是输出与输入相加,所有卷积使用conBN
    def__init__(self,input_c:int,kernet:int,expanded_c;int,
    out_c:int,
    use_se:bool,
    activation:str,
    stride:int,
    width_multi:float):
        self.input_c=self.adjust_channels(input_c,width_nulti)
        self.kernel=kernel
        self.expanded_c=self.adjust_channels(expanded_c,width_multi)
        self.out_c=self.adjust_channels(out_c,width_multi)
        self.use_se=use_se
        self.use_hs=activation=="HS"
        #是否使用新的激活函数
        self.stride=stride
    @staticmethod
    def adjust_channels(channels:in,width_multi:float):
        return _make_divisible(channels*width_muti,8)

class InvertedResidual(nn.Module):
    def__init__(self,
    cnf:InvertedResidualConfig,
    norm_layer:Callable[...,nn.Module]):
        super(InvertedResidual,self).__init__()
        if cnf.stride not in [1,2]:
            raise ValueError("illegal stride value.")
            self.use_res_connect=(cnf.stride==1 and cnf.input_c ==cnf.out_c)
            layers:List[nn.Module]=[] #类型是NN.module
            activation_layer=nn.Hardswish if cnf.use_hs else nn.ReLU
            if cnf.expanded_c!=cnf.input_c
            #由于第一层输入输出一样 无扩大因子
                layers.append(ConvBNActivation(cnf.input_c,
                cnf.expanded_c,
                kernel_size=1,
                norm_layer=norm_layer,
                activation_layer=activation_layer))
            layers.append(ConvBNActivation(cnf.expanded_c,
            cnf.expanded_c,
            kernel_size=cnf.kernel,
            stride=cnf.stride,
            groups=cnf.expanded_c,
            #DW
            norm_layer=norm_layer,
            activation_layer=activation_layer))
            if cnf.use_se:
                layers.append(SqueezeExcitation(cnf.expanded_c))
            #SE
            layers.append(ConvBNActivation(cnf.expanded_c,cnf.out_c,kernel_size=1,norm_layer=norm_layer,activation_layger=nn.Identity))
            #PW
            self.block=nn.Sequential(*layers)
            self.out_channels=cnf.out_c
            self.is_strided=cnf.stride>1
     def forward(self,x:Tensor)->Tensor:
         result=self.block(x)
         if self.use_res_connect:
             retult+=x
         return result
 class MobileNetV3(nn.Module):
     def__init__(self,
     inverted_residual_setting:List[InvertedResidualConfig],
     last_channel:int,
     num_classes:int=1000,
     block:Optional[Callable[...,nn.Module]]=None,
     norm_layer:Optional[Callable[...,nn.Module]]=None):
         super(MobileNetV3,self).__init__():
         if not inverted_residual_setting:
             raise ValueError("The inverted_residual_setting should not be empty.")
         elif not(isinstance(inverted_residual_setting,List) and
         all([isinstance(s,InvertedResidualConfig) for s in inverted_residual_setting])):
             raise TypeError("The inverted_residual_setting should be 
             List[InvertedResidualConfig]")
         if block is None:
             block=InvertedResidual
         if norm_layer if None:
             norm_layer =partial(nn.BatchNorm2d,
             eps=0.001,momentum=0.01) #存入默认参数
         layers:List[nn.Module]=[]
         firstconv_output_c=inverted_residual_setting[0].input_c
         layers.append(ConvBNActivation(3,firstconv_output_C,
         kernel_size=3,
         stride=2,
         norm_layer=norm_layer,
         activation_layer=nn.Hardswish))
         for cnf in inverted_residual_setting:
             layers.append(block(cnf,norm_layer))
         lastconv_input_c=inverted_residual_setting[-1].out_c
         lastconv_output_c=6*lastconv_input_c
         layers.append(ConvBNActivation(lastconv_input_c,
         lastconv_output_c,
         kernel_size=1,
         norm_layer=norm_layer,
         activation_layer=nn.Hardswish))
         self.features=nn.Sequential(*layers)
         self.avgpool=nn.AdaptiveAvgPool2d(1)
         self.classifier=nn.Sequential(nn.Linear(lastconv_output_c,last_channel,
         nn.Hardwish(inpalce=True),
         nn.Dropout(p=0.2,inplace=True),
         nn.Linear(last_channel,num_classes))
         for m in self.module():
             if isinstance(m,nn.Conv2d):
                 nn.init.kaiming_normal_(m.weight,mode="fan_out")
                 if m.bias if not None:
                     nn.init.zeros_(m.bias)
                 elif isinstance(m,(nn.BatchNorm2d,nn.GroupNorm)):
                     nn.init.ones_(m.weight)
                     nn.init.zeros_(m.bias)
                 elif isinstance(m,nn.Linear):
                     nn.init.normal_(m.weight,0,0.01)
                     nn.init.zeros_(m.bias)
   def _forward_impl(self ,x:Tensor)->Tensor:
       x=self.feature(x)
       x=self.avgpool(x)
       x=torch.flatten(x,1)
       x=self.classifier(x)
       return x
   def forward(self,x:Tensor)->Tensor:
       return self._forward_impl(x)
             
   def mobilenet_v3_large(num_classes:int=1000,reduced_tail:bool =False)->MobileNetV3:
       width_multi=1.0
       bneck_conf=partial(InvertedResidualConfig,width_multi=width_multh)
       adjust_channels=partial(InvertedResidualConfig.adjust_channels,
       width_multi=width_multi)
       reduce_divider=2 if reducted_tail else 1
       inverted_residual_setting = [
        # input_c, kernel, expanded_c, out_c, use_se, activation, stride
        bneck_conf(16, 3, 16, 16, False, "RE", 1),
        bneck_conf(16, 3, 64, 24, False, "RE", 2),  # C1
        bneck_conf(24, 3, 72, 24, False, "RE", 1),
        bneck_conf(24, 5, 72, 40, True, "RE", 2),  # C2
        bneck_conf(40, 5, 120, 40, True, "RE", 1),
        bneck_conf(40, 5, 120, 40, True, "RE", 1),
        bneck_conf(40, 3, 240, 80, False, "HS", 2),  # C3
        bneck_conf(80, 3, 200, 80, False, "HS", 1),
        bneck_conf(80, 3, 184, 80, False, "HS", 1),
        bneck_conf(80, 3, 184, 80, False, "HS", 1),
        bneck_conf(80, 3, 480, 112, True, "HS", 1),
        bneck_conf(112, 3, 672, 112, True, "HS", 1),
        bneck_conf(112, 5, 672, 160 // reduce_divider, True, "HS", 2),  # C4
        bneck_conf(160 // reduce_divider, 5, 960 // reduce_divider, 160 // reduce_divider, True, "HS", 1),
        bneck_conf(160 // reduce_divider, 5, 960 // reduce_divider, 160 // reduce_divider, True, "HS", 1),
    ]
       last_channel = adjust_channels(1280 // reduce_divider)  # C5

       return MobileNetV3(inverted_residual_setting=inverted_residual_setting,
                       last_channel=last_channel,
                       num_classes=num_classes
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