Tensorflow教程(2)

通过Tensorflow实现经典的卷积神经网络

image-20230505093533845

一、LeNet

卷积神经网络的开山之作(1998)

文章链接:Gradient-Based Learning Applied to Document Recognition

论文解读:Lenet5经典论文解读

1.代码实现:

(1)网络架构

LeNet时代没有BN以及Dropout

image-20230504114615690

image-20230504114719184

(2)代码
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"""
Tensorflow实现LeNet
"""
import tensorflow as tf
import os
import numpy as np
from matplotlib import pyplot as plt


np.set_printoptions(threshold=np.inf)

# 加载数据集
cifar10 = tf.keras.datasets.cifar10
(x_train, y_train), (x_test, y_test) = cifar10.load_data()
# 对输入数据进行皈依化
x_train, x_test = x_train / 255.0, x_test / 255.0


class LeNet5(tf.keras.Model):
def __init__(self):
super(LeNet5, self).__init__()
self.c1 = tf.keras.layers.Conv2D(filters=6, kernel_size=(5, 5),
activation='sigmoid')
self.p1 = tf.keras.layers.MaxPool2D(pool_size=(2, 2), strides=2)

self.c2 = tf.keras.layers.Conv2D(filters=16, kernel_size=(5, 5),
activation='sigmoid')
self.p2 = tf.keras.layers.MaxPool2D(pool_size=(2, 2), strides=2)

self.flatten = tf.keras.layers.Flatten()
self.f1 = tf.keras.layers.Dense(120, activation='sigmoid')
self.f2 = tf.keras.layers.Dense(84, activation='sigmoid')
self.f3 = tf.keras.layers.Dense(10, activation='softmax')

def call(self, x):
x = self.c1(x)
x = self.p1(x)

x = self.c2(x)
x = self.p2(x)

x = self.flatten(x)
x = self.f1(x)
x = self.f2(x)
y = self.f3(x)
return y


model = LeNet5()

model.compile(optimizer='adam',
loss=tf.keras.losses.SparseCategoricalCrossentropy(from_logits=False),
metrics=['sparse_categorical_accuracy'])

checkpoint_save_path = "./checkpoint/LeNet5.ckpt"
if os.path.exists(checkpoint_save_path + '.index'):
print('-------------load the model-----------------')
model.load_weights(checkpoint_save_path)

cp_callback = tf.keras.callbacks.ModelCheckpoint(filepath=checkpoint_save_path,
save_weights_only=True,
save_best_only=True)

history = model.fit(x_train, y_train, batch_size=32, epochs=5, validation_data=(x_test, y_test), validation_freq=1,
callbacks=[cp_callback])
model.summary()

# print(model.trainable_variables)
file = open('./weights.txt', 'w')
for v in model.trainable_variables:
file.write(str(v.name) + '\n')
file.write(str(v.shape) + '\n')
file.write(str(v.numpy()) + '\n')
file.close()

############################################### show ###############################################

# 显示训练集和验证集的acc和loss曲线
acc = history.history['sparse_categorical_accuracy']
val_acc = history.history['val_sparse_categorical_accuracy']
loss = history.history['loss']
val_loss = history.history['val_loss']

plt.subplot(1, 2, 1)
plt.plot(acc, label='Training Accuracy')
plt.plot(val_acc, label='Validation Accuracy')
plt.title('Training and Validation Accuracy')
plt.legend()

plt.subplot(1, 2, 2)
plt.plot(loss, label='Training Loss')
plt.plot(val_loss, label='Validation Loss')
plt.title('Training and Validation Loss')
plt.legend()
plt.show()

二、AlexNet

1.代码实现

论文原文中使用的是LRN操作,与BN操作类似

(1)网络架构

image-20230504184654735

image-20230504185755388

(2)代码
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import tensorflow as tf
import os
import numpy as np
from matplotlib import pyplot as plt
from tensorflow.keras.layers import Conv2D, BatchNormalization, Activation, MaxPool2D, Dropout, Flatten, Dense
from tensorflow.keras import Model

np.set_printoptions(threshold=np.inf)

cifar10 = tf.keras.datasets.cifar10
(x_train, y_train), (x_test, y_test) = cifar10.load_data()
x_train, x_test = x_train / 255.0, x_test / 255.0


class AlexNet8(Model):
def __init__(self):
super(AlexNet8, self).__init__()
self.c1 = Conv2D(filters=96, kernel_size=(3, 3))
self.b1 = BatchNormalization()
self.a1 = Activation('relu')
self.p1 = MaxPool2D(pool_size=(3, 3), strides=2)

self.c2 = Conv2D(filters=256, kernel_size=(3, 3))
self.b2 = BatchNormalization()
self.a2 = Activation('relu')
self.p2 = MaxPool2D(pool_size=(3, 3), strides=2)

self.c3 = Conv2D(filters=384, kernel_size=(3, 3), padding='same',
activation='relu')

self.c4 = Conv2D(filters=384, kernel_size=(3, 3), padding='same',
activation='relu')

self.c5 = Conv2D(filters=256, kernel_size=(3, 3), padding='same',
activation='relu')
self.p3 = MaxPool2D(pool_size=(3, 3), strides=2)

self.flatten = Flatten()
self.f1 = Dense(2048, activation='relu')
self.d1 = Dropout(0.5)
self.f2 = Dense(2048, activation='relu')
self.d2 = Dropout(0.5)
self.f3 = Dense(10, activation='softmax')

def call(self, x):
x = self.c1(x)
x = self.b1(x)
x = self.a1(x)
x = self.p1(x)

x = self.c2(x)
x = self.b2(x)
x = self.a2(x)
x = self.p2(x)

x = self.c3(x)

x = self.c4(x)

x = self.c5(x)
x = self.p3(x)

x = self.flatten(x)
x = self.f1(x)
x = self.d1(x)
x = self.f2(x)
x = self.d2(x)
y = self.f3(x)
return y


model = AlexNet8()

model.compile(optimizer='adam',
loss=tf.keras.losses.SparseCategoricalCrossentropy(from_logits=False),
metrics=['sparse_categorical_accuracy'])

checkpoint_save_path = "./checkpoint/AlexNet8.ckpt"
if os.path.exists(checkpoint_save_path + '.index'):
print('-------------load the model-----------------')
model.load_weights(checkpoint_save_path)

cp_callback = tf.keras.callbacks.ModelCheckpoint(filepath=checkpoint_save_path,
save_weights_only=True,
save_best_only=True)

history = model.fit(x_train, y_train, batch_size=32, epochs=5, validation_data=(x_test, y_test), validation_freq=1,
callbacks=[cp_callback])
model.summary()

# print(model.trainable_variables)
file = open('./weight_txt/weights.txt', 'w')
for v in model.trainable_variables:
file.write(str(v.name) + '\n')
file.write(str(v.shape) + '\n')
file.write(str(v.numpy()) + '\n')
file.close()

############################################### show ###############################################

# 显示训练集和验证集的acc和loss曲线
acc = history.history['sparse_categorical_accuracy']
val_acc = history.history['val_sparse_categorical_accuracy']
loss = history.history['loss']
val_loss = history.history['val_loss']

plt.subplot(1, 2, 1)
plt.plot(acc, label='Training Accuracy')
plt.plot(val_acc, label='Validation Accuracy')
plt.title('Training and Validation Accuracy')
plt.legend()

plt.subplot(1, 2, 2)
plt.plot(loss, label='Training Loss')
plt.plot(val_loss, label='Validation Loss')
plt.title('Training and Validation Loss')
plt.legend()
plt.show()

3.VGGNet