目錄
前言
一、前期工作
1.1 設置GPU
1.2 導入數據
輸出
二、數據預處理
2.1 加載數據
2.2 再次檢查數據
2.3 配置數據集
2.4 可視化數據
三、構建VGG-16網絡
3.1 VGG-16網絡介紹
3.2 搭建VGG-16模型
四、編譯
五、訓練模型
六、模型評估
七、預測
總結
前言
🍨 本文為
中的學習記錄博客
🍖 原作者:
說在前面
1)本周任務:了解model.train_on_batch()
并運用;了解tqdm,并使用tqdm實現可視化進度條;
2)運行環境:Python3.6、Pycharm2020、tensorflow2.4.0
一、前期工作
1.1 設置GPU
代碼如下:
import os
os.environ["CUDA_VISIBLE_DEVICES"]="0"
os.environ["TF_CPP_MIN_LOG_LEVEL"]='3' # 忽略 Error
#隱藏警告
import warnings
warnings.filterwarnings('ignore')
# 1.1 設置GPU
import tensorflow as tf
gpus = tf.config.list_physical_devices("GPU")
if gpus:tf.config.experimental.set_memory_growth(gpus[0], True) #設置GPU顯存用量按需使用tf.config.set_visible_devices([gpus[0]],"GPU")
# 打印顯卡信息,確認GPU可用
print(gpus)
輸出:[PhysicalDevice(name='/physical_device:GPU:0', device_type='GPU')]
??????前期我沒有使用GPU就采用的CPU訓練速度很慢,雖然安裝了tensorflow-gpu但還是用的CPU因為我的cudnn和cudatoolkit之前沒配置成功,然后我補充安裝。這里出線會打印很多關于gpu調用的日志信息,會很影響我們對訓練過程和打印信息的關注度,這里我在import tensorflow之前先通過下面的設置來控制打印的內容
import os
os.environ["CUDA_VISIBLE_DEVICES"]="0"
os.environ["TF_CPP_MIN_LOG_LEVEL"]='3'?
TF_CPP_MIN_LOG_LEVEL 取值 0 : 0也是默認值,輸出所有信息
TF_CPP_MIN_LOG_LEVEL 取值 1 : 屏蔽通知信息
TF_CPP_MIN_LOG_LEVEL 取值 2 : 屏蔽通知信息和警告信息
TF_CPP_MIN_LOG_LEVEL 取值 3 : 屏蔽通知信息、警告信息和報錯信息? ? ? ? ? ? ? ? ?
參考自:https://blog.csdn.net/xiaoqiaoliushuiCC/article/details/124435241
1.2 導入數據
代碼如下:
# 1.2 導入數據
import matplotlib.pyplot as plt
# 支持中文
plt.rcParams['font.sans-serif'] = ['SimHei'] # 用來正常顯示中文標簽
plt.rcParams['axes.unicode_minus'] = False # 用來正常顯示負號
import os,PIL,pathlib
data_dir = "./data"
data_dir = pathlib.Path(data_dir)
image_count = len(list(data_dir.glob('*/*')))
print("圖片總數為:",image_count)
輸出
圖片總數為:??3400
二、數據預處理
2.1 加載數據
使用image_dataset_from_directory
方法將磁盤中的數據加載到tf.data.Dataset,
tf.keras.preprocessing.image_dataset_from_directory():是 TensorFlow 的 Keras 模塊中的一個函數,用于從目錄中創建一個圖像數據集(dataset)。這個函數可以以更方便的方式加載圖像數據,用于訓練和評估神經網絡模型
測試集與驗證集的關系:
- 驗證集并沒有參與訓練過程梯度下降過程的,狹義上來講是沒有參與模型的參數訓練更新的。
- 但是廣義上來講,驗證集存在的意義確實參與了一個“人工調參”的過程,我們根據每一個epoch訓練之后模型在valid data上的表現來決定是否需要訓練進行early stop,或者根據這個過程模型的性能變化來調整模型的超參數,如學習率,batch_size等等。因此,我們也可以認為,驗證集也參與了訓練,但是并沒有使得模型去overfit驗證集
- 因此,我們也可以認為,驗證集也參與了訓練,但是并沒有使得模型去overfit驗證集
代碼如下:
# 二、數據預處理
# 2.1 加載數據
batch_size = 8
img_height = 224
img_width = 224
train_ds = tf.keras.preprocessing.image_dataset_from_directory(data_dir,validation_split=0.2,subset="training",seed=12,image_size=(img_height, img_width),batch_size=batch_size)
val_ds = tf.keras.preprocessing.image_dataset_from_directory(data_dir,validation_split=0.2,subset="validation",seed=12,image_size=(img_height, img_width),batch_size=batch_size)
class_names = train_ds.class_names
print(class_names)
輸出如下:
['cat', 'dog']
2.2 再次檢查數據
代碼如下:
# 2.2 再次檢查數據
for image_batch, labels_batch in train_ds:print(image_batch.shape)print(labels_batch.shape)break
輸出:
(8, 224, 224, 3)
(8,)
2.3 配置數據集
代碼如下:
# 2.3 配置數據集
AUTOTUNE = tf.data.AUTOTUNEdef preprocess_image(image,label):return (image/255.0,label)
# 歸一化處理
train_ds = train_ds.map(preprocess_image, num_parallel_calls=AUTOTUNE)
val_ds = val_ds.map(preprocess_image, num_parallel_calls=AUTOTUNE)
train_ds = train_ds.cache().shuffle(1000).prefetch(buffer_size=AUTOTUNE)
val_ds = val_ds.cache().prefetch(buffer_size=AUTOTUNE)
2.4 可視化數據
代碼如下:
plt.figure(figsize=(15, 10)) # 圖形的寬為15高為10
for images, labels in train_ds.take(1):for i in range(8):ax = plt.subplot(5, 8, i + 1)plt.imshow(images[i])plt.title(class_names[labels[i]])plt.axis("off")
輸出:
三、構建VGG-16網絡
3.1 VGG-16網絡介紹
結構說明:
- 13個卷積層(Convolutional Layer),分別用
blockX_convX
表示 - 3個全連接層(Fully connected Layer),分別用
fcX
與predictions
表示 - 5個池化層(Pool layer),分別用
blockX_pool
表示
網絡結構圖如下(包含了16個隱藏層--13個卷積層和3個全連接層,故稱為VGG-16)
???
?
3.2 搭建VGG-16模型
代碼如下:
# 三、構建VGG-16網絡
from tensorflow.keras import layers, models, Input
from tensorflow.keras.models import Model
from tensorflow.keras.layers import Conv2D, MaxPooling2D, Dense, Flatten, Dropoutdef VGG16(nb_classes, input_shape):input_tensor = Input(shape=input_shape)# 1st blockx = Conv2D(64, (3,3), activation='relu', padding='same',name='block1_conv1')(input_tensor)x = Conv2D(64, (3,3), activation='relu', padding='same',name='block1_conv2')(x)x = MaxPooling2D((2,2), strides=(2,2), name = 'block1_pool')(x)# 2nd blockx = Conv2D(128, (3,3), activation='relu', padding='same',name='block2_conv1')(x)x = Conv2D(128, (3,3), activation='relu', padding='same',name='block2_conv2')(x)x = MaxPooling2D((2,2), strides=(2,2), name = 'block2_pool')(x)# 3rd blockx = Conv2D(256, (3,3), activation='relu', padding='same',name='block3_conv1')(x)x = Conv2D(256, (3,3), activation='relu', padding='same',name='block3_conv2')(x)x = Conv2D(256, (3,3), activation='relu', padding='same',name='block3_conv3')(x)x = MaxPooling2D((2,2), strides=(2,2), name = 'block3_pool')(x)# 4th blockx = Conv2D(512, (3,3), activation='relu', padding='same',name='block4_conv1')(x)x = Conv2D(512, (3,3), activation='relu', padding='same',name='block4_conv2')(x)x = Conv2D(512, (3,3), activation='relu', padding='same',name='block4_conv3')(x)x = MaxPooling2D((2,2), strides=(2,2), name = 'block4_pool')(x)# 5th blockx = Conv2D(512, (3,3), activation='relu', padding='same',name='block5_conv1')(x)x = Conv2D(512, (3,3), activation='relu', padding='same',name='block5_conv2')(x)x = Conv2D(512, (3,3), activation='relu', padding='same',name='block5_conv3')(x)x = MaxPooling2D((2,2), strides=(2,2), name = 'block5_pool')(x)# full connectionx = Flatten()(x)x = Dense(4096, activation='relu', name='fc1')(x)x = Dense(4096, activation='relu', name='fc2')(x)output_tensor = Dense(nb_classes, activation='softmax', name='predictions')(x)model = Model(input_tensor, output_tensor)return modelmodel=VGG16(1000, (img_width, img_height, 3))
model.summary()
模型結構打印如下:
?Model: "model"
_________________________________________________________________
Layer (type) ? ? ? ? ? ? ? ? Output Shape ? ? ? ? ? ? ?Param # ??
=================================================================
input_1 (InputLayer) ? ? ? ? [(None, 224, 224, 3)] ? ? 0 ? ? ? ??
_________________________________________________________________
block1_conv1 (Conv2D) ? ? ? ?(None, 224, 224, 64) ? ? ?1792 ? ? ?
_________________________________________________________________
block1_conv2 (Conv2D) ? ? ? ?(None, 224, 224, 64) ? ? ?36928 ? ??
_________________________________________________________________
block1_pool (MaxPooling2D) ? (None, 112, 112, 64) ? ? ?0 ? ? ? ??
_________________________________________________________________
block2_conv1 (Conv2D) ? ? ? ?(None, 112, 112, 128) ? ? 73856 ? ??
_________________________________________________________________
block2_conv2 (Conv2D) ? ? ? ?(None, 112, 112, 128) ? ? 147584 ? ?
_________________________________________________________________
block2_pool (MaxPooling2D) ? (None, 56, 56, 128) ? ? ? 0 ? ? ? ??
_________________________________________________________________
block3_conv1 (Conv2D) ? ? ? ?(None, 56, 56, 256) ? ? ? 295168 ? ?
_________________________________________________________________
block3_conv2 (Conv2D) ? ? ? ?(None, 56, 56, 256) ? ? ? 590080 ? ?
_________________________________________________________________
block3_conv3 (Conv2D) ? ? ? ?(None, 56, 56, 256) ? ? ? 590080 ? ?
_________________________________________________________________
block3_pool (MaxPooling2D) ? (None, 28, 28, 256) ? ? ? 0 ? ? ? ??
_________________________________________________________________
block4_conv1 (Conv2D) ? ? ? ?(None, 28, 28, 512) ? ? ? 1180160 ??
_________________________________________________________________
block4_conv2 (Conv2D) ? ? ? ?(None, 28, 28, 512) ? ? ? 2359808 ??
_________________________________________________________________
block4_conv3 (Conv2D) ? ? ? ?(None, 28, 28, 512) ? ? ? 2359808 ??
_________________________________________________________________
block4_pool (MaxPooling2D) ? (None, 14, 14, 512) ? ? ? 0 ? ? ? ??
_________________________________________________________________
block5_conv1 (Conv2D) ? ? ? ?(None, 14, 14, 512) ? ? ? 2359808 ??
_________________________________________________________________
block5_conv2 (Conv2D) ? ? ? ?(None, 14, 14, 512) ? ? ? 2359808 ??
_________________________________________________________________
block5_conv3 (Conv2D) ? ? ? ?(None, 14, 14, 512) ? ? ? 2359808 ??
_________________________________________________________________
block5_pool (MaxPooling2D) ? (None, 7, 7, 512) ? ? ? ? 0 ? ? ? ??
_________________________________________________________________
flatten (Flatten) ? ? ? ? ? ?(None, 25088) ? ? ? ? ? ? 0 ? ? ? ??
_________________________________________________________________
fc1 (Dense) ? ? ? ? ? ? ? ? ?(None, 4096) ? ? ? ? ? ? ?102764544?
_________________________________________________________________
fc2 (Dense) ? ? ? ? ? ? ? ? ?(None, 4096) ? ? ? ? ? ? ?16781312 ?
_________________________________________________________________
predictions (Dense) ? ? ? ? ?(None, 1000) ? ? ? ? ? ? ?4097000 ??
=================================================================
Total params: 138,357,544
Trainable params: 138,357,544
Non-trainable params: 0
四、編譯
代碼如下:
model.compile(optimizer="adam",loss='sparse_categorical_crossentropy',metrics=['accuracy'])
五、訓練模型
代碼如下:
# 五、訓練模型
from tqdm import tqdm
import tensorflow.keras.backend as Kepochs = 10
lr = 1e-4# 記錄訓練數據,方便后面的分析
history_train_loss = []
history_train_accuracy = []
history_val_loss = []
history_val_accuracy = []
for epoch in range(epochs):train_total = len(train_ds)val_total = len(val_ds)with tqdm(total=train_total, desc=f'Epoch {epoch + 1}/{epochs}', mininterval=1, ncols=100) as pbar:lr = lr * 0.92K.set_value(model.optimizer.lr, lr)for image, label in train_ds:history = model.train_on_batch(image, label)train_loss = history[0]train_accuracy = history[1]pbar.set_postfix({"loss": "%.4f" % train_loss,"accuracy": "%.4f" % train_accuracy,"lr": K.get_value(model.optimizer.lr)})pbar.update(1)history_train_loss.append(train_loss)history_train_accuracy.append(train_accuracy)print('開始驗證!')with tqdm(total=val_total, desc=f'Epoch {epoch + 1}/{epochs}', mininterval=0.3, ncols=100) as pbar:for image, label in val_ds:history = model.test_on_batch(image, label)val_loss = history[0]val_accuracy = history[1]pbar.set_postfix({"loss": "%.4f" % val_loss,"accuracy": "%.4f" % val_accuracy})pbar.update(1)history_val_loss.append(val_loss)history_val_accuracy.append(val_accuracy)print('結束驗證!')print("驗證loss為:%.4f" % val_loss)print("驗證準確率為:%.4f" % val_accuracy)
打印訓練過程:
?
六、模型評估
代碼如下:
epochs_range = range(epochs)
plt.figure(figsize=(12, 4))
plt.subplot(1, 2, 1)plt.plot(epochs_range, history_train_accuracy, label='Training Accuracy')
plt.plot(epochs_range, history_val_accuracy, label='Validation Accuracy')
plt.legend(loc='lower right')
plt.title('Training and Validation Accuracy')plt.subplot(1, 2, 2)
plt.plot(epochs_range, history_train_loss, label='Training Loss')
plt.plot(epochs_range, history_val_loss, label='Validation Loss')
plt.legend(loc='upper right')
plt.title('Training and Validation Loss')
plt.show()
訓練結果可視化如下:
???
七、預測
代碼如下:
# 七、預測
import numpy as np
# 采用加載的模型(new_model)來看預測結果
plt.figure(figsize=(18, 3)) # 圖形的寬為18高為5
plt.suptitle("預測結果展示")
for images, labels in val_ds.take(1):for i in range(8):ax = plt.subplot(1, 8, i + 1)# 顯示圖片plt.imshow(images[i].numpy())# 需要給圖片增加一個維度img_array = tf.expand_dims(images[i], 0)# 使用模型預測圖片中的人物predictions = model.predict(img_array)plt.title(class_names[np.argmax(predictions)])plt.axis("off")
輸出:
1/1 [==============================] - 0s 129ms/step
1/1 [==============================] - 0s 19ms/step
1/1 [==============================] - 0s 18ms/step
1/1 [==============================] - 0s 18ms/step
1/1 [==============================] - 0s 17ms/step
1/1 [==============================] - 0s 18ms/step
1/1 [==============================] - 0s 17ms/step
1/1 [==============================] - 0s 17ms/step
總結
- Tensorflow訓練過程中打印多余信息的處理,并且引入了進度條的顯示方式,更加方便及時查看模型訓練過程中的情況,可以及時打印各項指標
- 修改了以往的model.fit()訓練方法,改用model.train_on_batch方法。兩種方法的比較:
model.fit()
:用起來十分簡單,對新手非常友好;model.train_on_batch()
:封裝程度更低,可以玩更多花樣 - 完成了VGG-16基于Tensorflow下的搭建、訓練等工作,對比分析了pytorch和tensorflow兩個框架下實現同種任務的異同;
- 完成VGG-16對貓狗圖片的高精度識別