- 🍨 本文为🔗365天深度学习训练营 中的学习记录博客
- 🍖 原作者:K同学啊
具体实现
(一)环境
语言环境:Python 3.10
编 译 器: PyCharm
框 架: Pytorch
(二)具体步骤
时间关系,代码很差…
1. utils.py
针对数据文件的目录情况进行了优化
import torch
import pathlib
import matplotlib.pyplot as plt
from torchvision.transforms import transforms # 第一步:设置GPU
def USE_GPU(): if torch.cuda.is_available(): print('CUDA is available, will use GPU') device = torch.device("cuda") else: print('CUDA is not available. Will use CPU') device = torch.device("cpu") return device temp_dict = dict()
def recursive_iterate(path): """ 根据所提供的路径遍历该路径下的所有子目录,列出所有子目录下的文件 :param path: 路径 :return: 返回最后一级目录的数据 """ path = pathlib.Path(path) for file in path.iterdir(): if file.is_file(): temp_key = str(file).split('\\')[-2] if temp_key in temp_dict: temp_dict.update({temp_key: temp_dict[temp_key] + 1}) else: temp_dict.update({temp_key: 1}) # print(file) elif file.is_dir(): recursive_iterate(file) return temp_dict def data_from_directory(directory, train_dir=None, test_dir=None, show=False): """ 提供是的数据集是文件形式的,提供目录方式导入数据,简单分析数据并返回数据分类 :param test_dir: 是否设置了测试集目录 :param train_dir: 是否设置了训练集目录 :param directory: 数据集所在目录 :param show: 是否需要以柱状图形式显示数据分类情况,默认显示 :return: 数据分类列表,类型: list """ global total_image print("数据目录:{}".format(directory)) data_dir = pathlib.Path(directory) # for d in data_dir.glob('**/*'): # **/*通配符可以遍历所有子目录 # if d.is_dir(): # print(d) class_name = [] total_image = 0 temp_sum = 0 if train_dir is None or test_dir is None: data_path = list(data_dir.glob('*')) class_name = [str(path).split('\\')[-1] for path in data_path] print("数据分类: {}, 类别数量:{}".format(class_name, len(list(data_dir.glob('*'))))) total_image = len(list(data_dir.glob('*/*'))) print("图片数据总数: {}".format(total_image)) else: temp_dict.clear() train_data_path = directory + '/' + train_dir train_data_info = recursive_iterate(train_data_path) print("{}目录:{},{}".format(train_dir, train_data_path, train_data_info)) temp_dict.clear() test_data_path = directory + '/' + test_dir print("{}目录:{},{}".format(test_dir, test_data_path, recursive_iterate(test_data_path))) class_name = temp_dict.keys() if show: # 隐藏警告 import warnings warnings.filterwarnings("ignore") # 忽略警告信息 plt.rcParams['font.sans-serif'] = ['SimHei'] # 用来正常显示中文标签 plt.rcParams['axes.unicode_minus'] = False # 用来正常显示负号 plt.rcParams['figure.dpi'] = 100 # 分辨率 for i in class_name: data = len(list(pathlib.Path((directory + '\\' + i + '\\')).glob('*'))) plt.title('数据分类情况') plt.grid(ls='--', alpha=0.5) plt.bar(i, data) plt.text(i, data, str(data), ha='center', va='bottom') print("类别-{}:{}".format(i, data)) temp_sum += data plt.show() if temp_sum == total_image: print("图片数据总数检查一致") else: print("数据数据总数检查不一致,请检查数据集是否正确!") return class_name def get_transforms_setting(size): """ 获取transforms的初始设置 :param size: 图片大小 :return: transforms.compose设置 """ transform_setting = { 'train': transforms.Compose([ transforms.Resize(size), transforms.ToTensor(), transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225]) ]), 'test': transforms.Compose([ transforms.Resize(size), transforms.ToTensor(), transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225]) ]) } return transform_setting
**2.**model.py
将CNN网络模板写到一个单独文件里,方便调用。
import torch.nn as nn
import torch
import torch.nn.functional as Fclass Model_Shoes(nn.Module): def __init__(self, classNames): super(Model_Shoes, self).__init__() self.conv1 = nn.Sequential( nn.Conv2d(3, 12, kernel_size=5, padding=0), # 12*220*220 nn.BatchNorm2d(12), nn.ReLU()) self.conv2 = nn.Sequential( nn.Conv2d(12, 12, kernel_size=5, padding=0), # 12*216*216 nn.BatchNorm2d(12), nn.ReLU()) self.pool3 = nn.Sequential( nn.MaxPool2d(2)) # 12*108*108 self.conv4 = nn.Sequential( nn.Conv2d(12, 24, kernel_size=5, padding=0), # 24*104*104 nn.BatchNorm2d(24), nn.ReLU()) self.conv5 = nn.Sequential( nn.Conv2d(24, 24, kernel_size=5, padding=0), # 24*100*100 nn.BatchNorm2d(24), nn.ReLU()) self.pool6 = nn.Sequential( nn.MaxPool2d(2)) # 24*50*50 self.dropout = nn.Sequential( nn.Dropout(0.2)) self.fc = nn.Sequential( nn.Linear(24 * 50 * 50, len(classNames))) def forward(self, x): batch_size = x.size(0) x = self.conv1(x) # 卷积-BN-激活 x = self.conv2(x) # 卷积-BN-激活 x = self.pool3(x) # 池化 x = self.conv4(x) # 卷积-BN-激活 x = self.conv5(x) # 卷积-BN-激活 x = self.pool6(x) # 池化 x = self.dropout(x) x = x.view(batch_size, -1) # flatten 变成全连接网络需要的输入 (batch, 24*50*50) ==> (batch, -1), -1 此处自动算出的是24*50*50 x = self.fc(x) return x
3. config.py
将训练的相关参数写到config.py中
import argparse def get_options(parser=argparse.ArgumentParser()): parser.add_argument('--workers', type=int, default=0, help='Number of parallel workers') parser.add_argument('--batch-size', type=int, default=32, help='input batch size, default=32') parser.add_argument('--lr', type=float, default=1e-4, help='learning rate, default=0.0001') parser.add_argument('--epochs', type=int, default=50, help='number of epochs') parser.add_argument('--seed', type=int, default=112, help='random seed') parser.add_argument('--save-path', type=str, default='./models/', help='path to save checkpoints') opt = parser.parse_args() if opt: print(f'num_workers:{opt.workers}') print(f'batch_size:{opt.batch_size}') print(f'learn rate:{opt.lr}') print(f'epochs:{opt.epochs}') print(f'random seed:{opt.seed}') print(f'save_path:{opt.save_path}') return opt if __name__ == '__main__': opt = get_options()
**4. main.py
from torch import nn
from torchvision import datasets from Utils import USE_GPU, data_from_directory, get_transforms_setting
import torch
import os, PIL, pathlib
from model import Model_Shoes import config opt = config.get_options()
print(opt) device = USE_GPU() DATA_DIR = "./data/shoes"
classNames = data_from_directory(DATA_DIR, train_dir="train", test_dir="test")
print(list(classNames)) transforms_setting = get_transforms_setting([224, 224])
train_dataset = datasets.ImageFolder(DATA_DIR + "/train", transforms_setting['train'])
test_dataset = datasets.ImageFolder(DATA_DIR + "/test", transforms_setting['test'])
print(train_dataset.class_to_idx) batch_size = opt.batch_size
train_dl = torch.utils.data.DataLoader(train_dataset, batch_size=batch_size, shuffle=True)
test_dl = torch.utils.data.DataLoader(test_dataset, batch_size=batch_size, shuffle=True) for X, y in test_dl: print("Shape of X[N, C, H, W]:", X.shape) print("Shape of y", y.shape, y.dtype) break model = Model_Shoes(classNames).to(device)
print(model) # 训练循环
def train(dataloader, model, loss_fn, optimizer): size = len(dataloader.dataset) # 训练集的大小 num_batches = len(dataloader) # 批次数目, (size/batch_size,向上取整) train_loss, train_acc = 0, 0 # 初始化训练损失和正确率 for X, y in dataloader: # 获取图片及其标签 X, y = X.to(device), y.to(device) # 计算预测误差 pred = model(X) # 网络输出 loss = loss_fn(pred, y) # 计算网络输出和真实值之间的差距,targets为真实值,计算二者差值即为损失 # 反向传播 optimizer.zero_grad() # grad属性归零 loss.backward() # 反向传播 optimizer.step() # 每一步自动更新 # 记录acc与loss train_acc += (pred.argmax(1) == y).type(torch.float).sum().item() train_loss += loss.item() train_acc /= size train_loss /= num_batches return train_acc, train_loss def test(dataloader, model, loss_fn): size = len(dataloader.dataset) # 测试集的大小 num_batches = len(dataloader) # 批次数目, (size/batch_size,向上取整) test_loss, test_acc = 0, 0 # 当不进行训练时,停止梯度更新,节省计算内存消耗 with torch.no_grad(): for imgs, target in dataloader: imgs, target = imgs.to(device), target.to(device) # 计算loss target_pred = model(imgs) loss = loss_fn(target_pred, target) test_loss += loss.item() test_acc += (target_pred.argmax(1) == target).type(torch.float).sum().item() test_acc /= size test_loss /= num_batches return test_acc, test_loss def adjust_learning_rate(optimizer, epoch, start_lr): # 每 2 个epoch衰减到原来的 0.92 lr = start_lr * (0.92 ** (epoch // 2)) for param_group in optimizer.param_groups: param_group['lr'] = lr learn_rate = opt.lr # 初始学习率
optimizer = torch.optim.SGD(model.parameters(), lr=learn_rate) loss_fn = nn.CrossEntropyLoss() # 创建损失函数
epochs = opt.epochs train_loss = []
train_acc = []
test_loss = []
test_acc = [] for epoch in range(epochs): # 更新学习率(使用自定义学习率时使用) adjust_learning_rate(optimizer, epoch, learn_rate) model.train() epoch_train_acc, epoch_train_loss = train(train_dl, model, loss_fn, optimizer) # scheduler.step() # 更新学习率(调用官方动态学习率接口时使用) model.eval() epoch_test_acc, epoch_test_loss = test(test_dl, model, loss_fn) train_acc.append(epoch_train_acc) train_loss.append(epoch_train_loss) test_acc.append(epoch_test_acc) test_loss.append(epoch_test_loss) # 获取当前的学习率 lr = optimizer.state_dict()['param_groups'][0]['lr'] template = ('Epoch:{:2d}, Train_acc:{:.1f}%, Train_loss:{:.3f}, Test_acc:{:.1f}%, Test_loss:{:.3f}, Lr:{:.2E}') print(template.format(epoch + 1, epoch_train_acc * 100, epoch_train_loss, epoch_test_acc * 100, epoch_test_loss, lr))
print('Done') import matplotlib.pyplot as plt
#隐藏警告
import warnings
warnings.filterwarnings("ignore") #忽略警告信息
plt.rcParams['font.sans-serif'] = ['SimHei'] # 用来正常显示中文标签
plt.rcParams['axes.unicode_minus'] = False # 用来正常显示负号
plt.rcParams['figure.dpi'] = 100 #分辨率 epochs_range = range(epochs) plt.figure(figsize=(12, 3))
plt.subplot(1, 2, 1) plt.plot(epochs_range, train_acc, label='Training Accuracy')
plt.plot(epochs_range, test_acc, label='Test Accuracy')
plt.legend(loc='lower right')
plt.title('Training and Validation Accuracy') plt.subplot(1, 2, 2)
plt.plot(epochs_range, train_loss, label='Training Loss')
plt.plot(epochs_range, test_loss, label='Test Loss')
plt.legend(loc='upper right')
plt.title('Training and Validation Loss')
plt.show() # 模型保存
MODEL_SAVE_NAME = "cnn-shoes.pth"
torch.save(model.state_dict(), opt.save_path + MODEL_SAVE_NAME)
**5. 预测指定图片
import torch from model import Model_Shoes
from Utils import USE_GPU, get_transforms_setting
from PIL import Image from PIL import Image device = USE_GPU()
transform_setting = get_transforms_setting([224, 224]) classes = ['adidas', 'nike']
model = Model_Shoes(classes)
model.load_state_dict(torch.load('./models/cnn-shoes.pth', map_location=device))
model.to(device) def predict_one_image(image_path, model, transform, classes): test_img = Image.open(image_path).convert('RGB') # plt.imshow(test_img) # 展示预测的图片 test_img = transform(test_img) img = test_img.to(device).unsqueeze(0) model.eval() output = model(img) _, pred = torch.max(output, 1) pred_class = classes[pred] print(f'预测结果是:{pred_class}') # 预测训练集中的某张照片
predict_one_image(image_path='./mydata/shoes/1.png', model=model, transform=transform_setting['train'], classes=classes)
(三)总结
本次学习对于构建CNN网络中的 nn.BatchNorm2d()做了初步的了解,nn.BatchNorm2d()进行数据的归一化处理,这使得数据在进行Relu之前不会因为数据过大而导致网络性能的不稳定,BatchNorm2d()函数数学原理如下:
BatchNorm2d()内部的参数如下:
1.num_features:一般输入参数为batch_sizenum_featuresheight*width,即为其中特征的数量
2.eps:分母中添加的一个值,目的是为了计算的稳定性,默认为:1e-5
3.momentum:一个用于运行过程中均值和方差的一个估计参数(我的理解是一个稳定系数,类似于SGD中的momentum的系数)
4.affine:当设为true时,会给定可以学习的系数矩阵gamma和beta
参考链接:https://blog.csdn.net/bigFatCat_Tom/article/details/91619977