Pytorch---使用Pytorch进行鸟类的预测

一、代码中的数据集可以通过以下链接获取

百度网盘提取码：lala

二、代码运行环境

Pytorch-gpu==1.7.1
Python==3.8

三、数据集处理代码如下所示

import glob
import numpy as np
from torch.utils.data.dataset import T_co
from torchvision import transforms
from torch.utils import data
from PIL import Image
import matplotlib.pyplot as plt
import torch


class FeatureDataset(data.Dataset):
    def __getitem__(self, index):
        return self.feature_list[index], torch.as_tensor(data=self.label_list[index], dtype=torch.long)

    def __init__(self, feature_list, label_list):
        self.feature_list = feature_list
        self.label_list = label_list

    def __len__(self):
        return len(self.feature_list)


class BirdsDataset(data.Dataset):
    def __init__(self, img_path, labels, trans):
        self.imgs = img_path
        self.labels = labels
        self.trans = trans

    def __getitem__(self, index) -> T_co:
        imgg = self.imgs[index]
        label = self.labels[index]
        pil_img = Image.open(imgg)
        pil_img = pil_img.convert('RGB')
        img_tensor = self.trans(pil_img)
        return img_tensor, label

    def __len__(self):
        return len(self.imgs)


def loader_data():
    file_names = glob.glob(r'birds\*\*.jpg')
    classes = np.unique([name.split('\\')[1].split('.')[1] for name in file_names])
    index_classes = dict((index, cla) for index, cla in enumerate(classes))
    classes_index = dict((v, k) for k, v in index_classes.items())
    all_labels = []
    for name in file_names:
        for cla in classes:
            if cla in name:
                all_labels.append(classes_index.get(cla))
    np.random.seed(200)
    random_index = np.random.permutation(len(file_names))
    file_names = np.array(file_names)[random_index]
    all_labels = np.array(all_labels)[random_index]

    i = int(len(file_names) * 0.8)

    train_path = file_names[:i]
    train_label = all_labels[:i]

    test_path = file_names[i:]
    test_label = all_labels[i:]

    transform = transforms.Compose([
        transforms.Resize((224, 224)),
        transforms.ToTensor()
    ])

    train_ds = BirdsDataset(img_path=train_path, labels=train_label, trans=transform)
    test_ds = BirdsDataset(img_path=test_path, labels=test_label, trans=transform)

    train_dl = data.DataLoader(dataset=train_ds, batch_size=32, shuffle=True)
    test_dl = data.DataLoader(dataset=test_ds, batch_size=32)

    return train_dl, test_dl, index_classes


if __name__ == '__main__':
    a, b, c = loader_data()
    img_batch, label_batch = next(iter(b))
    plt.figure(figsize=(12, 8))
    for ii, (img, lab) in enumerate(zip(img_batch[:6], label_batch[:6])):
        img = img.permute(1, 2, 0).numpy()
        plt.subplot(2, 3, ii + 1)
        plt.axis('off')
        plt.title(c.get(lab.item()))
        plt.imshow(img)
    plt.show()

四、模型的构建代码如下所示

import torchvision
from torch import nn


class FCModel(nn.Module):
    def __init__(self, in_size, out_size):
        super().__init__()
        self.lin1 = nn.Linear(in_features=in_size, out_features=2048)
        self.lin2 = nn.Linear(in_features=2048, out_features=1024)
        self.lin3 = nn.Linear(in_features=1024, out_features=out_size)

    def forward(self, x):
        return self.lin3(self.lin2(self.lin1(x)))


def load_model():
    model = torchvision.models.densenet121(pretrained=True).features
    for parameter in model.parameters():
        parameter.requires_grad = False
    return model


if __name__ == '__main__':
    mol = load_model()
    print(mol)

五、模型的训练代码如下所示

import torch
import tqdm
from data_loader import loader_data, FeatureDataset
from model_loader import load_model, FCModel
from torch.utils import data
from torch import nn, optim
from sklearn.metrics import accuracy_score
import numpy as np
import os

# 环境配置
devices = 'cuda' if torch.cuda.is_available() else 'cpu'

# 加载数据
train_dl, test_dl, index_classes = loader_data()

# 加载模型
model = load_model()
model = model.to(devices)

# 开始进行特征提取
train_features = []
train_labels = []
tqdm_train_dl = tqdm.tqdm(iterable=train_dl, total=len(train_dl))
for img, lab in tqdm_train_dl:
    out = model(img.to(devices))
    out = out.view(out.size(0), -1)
    train_features.extend(out.cpu().data)
    train_labels.extend(lab)
tqdm_train_dl.close()

test_features = []
test_labels = []
tqdm_test_dl = tqdm.tqdm(iterable=test_dl, total=len(test_dl))
for img, lab in tqdm_test_dl:
    out = model(img.to(devices))
    out = out.view(out.size(0), -1)
    test_features.extend(out.cpu().data)
    test_labels.extend(lab)
tqdm_test_dl.close()

# 构建特征的数据集
train_feat_ds = FeatureDataset(feature_list=train_features, label_list=train_labels)
test_feat_ds = FeatureDataset(feature_list=test_features, label_list=test_labels)

train_feat_dl = data.DataLoader(dataset=train_feat_ds, batch_size=32, shuffle=True)
test_feat_dl = data.DataLoader(dataset=test_feat_ds, batch_size=32)

# 构建特征分类器
in_size = train_features[0].shape[0]
net = FCModel(in_size=in_size, out_size=200)
net = net.to(devices)

# 训练使用的配置
loss_fn = nn.CrossEntropyLoss()
optimizer = optim.Adam(params=net.parameters(), lr=0.00001)

# 开始进行训练

for epoch in range(100):
    net.train()
    train_accuracy_sum = []
    train_loss_sum = []
    train_tqdm = tqdm.tqdm(iterable=train_feat_dl, total=len(train_feat_dl))
    train_tqdm.set_description_str('Train epoch {:2d}'.format(epoch))
    for img_feature, img_label in train_tqdm:
        img_feature, img_label = img_feature.to(devices), img_label.to(devices)
        pred = net(img_feature)
        loss = loss_fn(pred, img_label)
        optimizer.zero_grad()
        loss.backward()
        optimizer.step()
        # 进行指标的展示
        train_loss_sum.append(loss.item())
        pred = torch.argmax(input=pred, dim=-1)
        train_accuracy_sum.append(accuracy_score(y_true=img_label.cpu().numpy(), y_pred=pred.cpu().numpy()))
        train_tqdm.set_postfix_str(
            'loss is {:14f}, accuracy is {:14f}'.format(np.mean(train_loss_sum), np.mean(train_accuracy_sum)))
    train_tqdm.close()

    with torch.no_grad():
        net.eval()
        test_accuracy_sum = []
        test_loss_sum = []
        test_tqdm = tqdm.tqdm(iterable=test_feat_dl, total=len(test_feat_dl))
        test_tqdm.set_description_str('Test epoch {:2d}'.format(epoch))
        for img_feature, img_label in test_tqdm:
            img_feature, img_label = img_feature.to(devices), img_label.to(devices)
            pred = net(img_feature)
            loss = loss_fn(pred, img_label)
            # 进行指标的展示
            test_loss_sum.append(loss.item())
            pred = torch.argmax(input=pred, dim=-1)
            test_accuracy_sum.append(accuracy_score(y_true=img_label.cpu().numpy(), y_pred=pred.cpu().numpy()))
            test_tqdm.set_postfix_str(
                'loss is {:14f}, accuracy is {:14f}'.format(np.mean(test_loss_sum), np.mean(test_accuracy_sum)))
        test_tqdm.close()

# 模型的保存
if not os.path.exists(os.path.join('model_data')):
    os.mkdir(os.path.join('model_data'))
torch.save(net.state_dict(), os.path.join('model_data', 'net.pth'))

六、模型的预测代码如下所示

from data_loader import loader_data
from model_loader import load_model, FCModel
import torch
import os
import matplotlib.pyplot as plt

# 环境变量的配置
device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')

# 数据的加载
train_dl, test_dl, index_classes = loader_data()
image, label = next(iter(test_dl))
image, label = image.to(device), label.to(device)

# 模型的加载
model = load_model()
model.eval()
net = FCModel(in_size=50176, out_size=200)
model_state_dict = torch.load(os.path.join('model_data', 'net.pth'))
net.load_state_dict(model_state_dict)
net.eval()
model = model.to(device=device)
net = net.to(device=device)

# 进行模型的预测
index = 5
with torch.no_grad():
    feature = model(image)
    feature = feature.view(feature.size(0), -1)
    pre = net(feature)
    pre = torch.argmax(input=pre, dim=-1)
    plt.axis('off')
    plt.title('predict result: ' + index_classes.get(pre[index].cpu().item()) + '\nlabel result: ' + index_classes.get(
        label[index].cpu().item()))
    plt.imshow(image[index].cpu().permute(1, 2, 0))
    plt.savefig('result.png')
    plt.show()

七、代码的运行结果如下所示