利用深度神经网络进行基本图像分类
此代码在colab已经经过测试并且可以查看TensorBoard：地址
环境：Tensorflow-2.1.0、Python3.6、google colab
In[1]:
import ssl
ssl._create_default_https_context = ssl._create_unverified_context
# 不知道为什么在本地的jupyter notebook上无法导入fashion_mnist数据集(本地需要，google colab不需要)
In[2]:
import matplotlib as mpl
import matplotlib.pyplot as plt
%matplotlib inline
import numpy as np
import sklearn
import pandas as pd
import os
import sys
import time
import tensorflow as tf
from tensorflow import keras as keras
from sklearn.preprocessing import StandardScaler
for module in mpl,np,pd,sklearn,tf,keras:
print(module.__name__,module.__version__)
# 打印版本库
Out[1]:
matplotlib 3.1.2
numpy 1.18.1
pandas 0.25.3
sklearn 0.22.1
tensorflow 2.1.0
tensorflow_core.keras 2.2.4-tf
In[3]:
fashion_mnist=keras.datasets.fashion_mnist
(x_train_all, y_train_all),(x_test, y_test)=fashion_mnist.load_data()
# 导入fashion_mnist数据集
In[4]
x_valid,x_train=x_train_all[:5000],x_train_all[5000:]
y_valid,y_train=y_train_all[:5000],y_train_all[5000:]
# fashion_mnist有6w个数据，前5k个为验证集，其中x为图片，y为序列号
print(x_valid.shape,y_valid.shape)
print(x_train.shape,y_valid.shape)
print(x_test.shape,y_test.shape)
# 打印数据集的格式
Out[2]
(5000, 28, 28) (5000,)
(55000, 28, 28) (5000,)
(10000, 28, 28) (10000,)
In[5]:
print(np.max(x_train),np.min(x_train))
# 打印数据集中的最大值和最小值
Out[3]:
255 0
In[6]:
# x= (x-u)/std
scaler=StandardScaler()
# x_train:[None, 28, 28] -> [None, 784]
x_train_scaled=scaler.fit_transform(x_train.astype(np.float32).reshape(-1,1)).reshape(-1,28,28)
#会自动记录方差u和均值std，并进行归一化
x_valid_scaled=scaler.transform(x_valid.astype(np.float32).reshape(-1,1)).reshape(-1,28,28)
# 会根据自动记录的方差u和均值std进行归一化
x_test_scaled=scaler.transform(x_test.astype(np.float32).reshape(-1,1)).reshape(-1,28,28)
# 会根据自动记录的方差u和均值std进行归一化
Out[4]:
2.0231433 -0.8105136
In[7]:
def show_single_image(img_arr):
plt.imshow(img_arr,cmap='binary')
plt.show()
# 打印单张图片
show_single_image(x_train[0])
Out[5]:
In[8]:
def show_images(n_rows,n_cols,x_data,y_data,class_names):
assert len(x_data)==len(y_data)
assert n_cols*n_rows<len(x_data)
plt.figure(figsize=(n_cols*1.4,n_rows*1.6))
for row in range(n_rows):
for col in range(n_cols):
index=n_cols*row+col
plt.subplot(n_rows,n_cols,index+1)
plt.imshow(x_data[index],cmap='binary',
interpolation='nearest')
plt.axis('off')
plt.title(class_names[y_data[index]])
plt.show()
# 打印n_rows行n_cols列的图片
class_names = ['T-shirt/top', 'Trouser', 'Pullover', 'Dress', 'Coat',
'Sandal', 'Shirt', 'Sneaker', 'Bag', 'Ankle boot']
# 所对应的名称
show_images(3,5,x_train,y_train,class_names)
Out[6]:
In[9]:
# 构建一个三层的神经网络
# model=keras.models.Sequential()
# model.add(keras.layers.Flatten(input_shape=[28,28])) # 展开成28*28的向量
# model.add(keras.layers.Dense(300,activation='relu')) # 全链接层，层数300，激活函数relu
# model.add(keras.layers.Dense(100,activation='relu'))
# model.add(keras.layers.Dense(10,activation='softmax')) # 有10个输出
# model=keras.models.Sequential([
# keras.layers.Flatten(input_shape=[28,28]),
# keras.layers.Dense(300,activation='relu'),
# keras.layers.Dense(100,activation='relu'),
# keras.layers.Dense(10,activation='softmax')
# ])
model=keras.models.Sequential()
model.add(keras.layers.Flatten(input_shape=[28,28]))
for _ in range(20):
model.add(keras.layers.Dense(100,activation='selu'))
# model.add(keras.layers.Dense(100,activation='relu'))
# model.add(keras.layers.BatchNormalization())
# 激活函数在前的后的批归一化
# model.add(keras.layers.Dense(100))
# model.add(keras.layers.BatchNormalization())
# model.add(keras.layers.Activation('relu'))
# model.add(keras.layers.Dropout(rate=0.5))
model.add(keras.layers.AlphaDropout(rate=0.5))
# AlphaDropout与Dropout的区别：1、均值方差不变 2、归一化性质不变
model.add(keras.layers.Dense(10,activation='softmax'))
# relu: y=max(0,x)
# softmax: 将向量变成概率分布 x=[x1,x2,x3]
# y=[e^x1/sum,e^x2/sum,e^x3/sum],sum=e^x1+e^x2+e^x3
# reason for sparse: y->index y->one_hot->[]
model.compile(loss='sparse_categorical_crossentropy',
optimizer='sgd',
metrics=['accuracy'])
tensorflow.keras.model.compile
In[10]:
model.layers
Out[7]:
[<tensorflow.python.keras.layers.core.Flatten at 0x136ef6a90>,
<tensorflow.python.keras.layers.core.Dense at 0x136ef6ad0>,
<tensorflow.python.keras.layers.core.Dense at 0x136eb5f90>,
<tensorflow.python.keras.layers.core.Dense at 0x13689dcd0>,
<tensorflow.python.keras.layers.core.Dense at 0x136ed6990>,
<tensorflow.python.keras.layers.core.Dense at 0x136894090>,
<tensorflow.python.keras.layers.core.Dense at 0x13689b450>,
<tensorflow.python.keras.layers.core.Dense at 0x13689b110>,
<tensorflow.python.keras.layers.core.Dense at 0x111477050>,
<tensorflow.python.keras.layers.core.Dense at 0x13a68c7d0>,
<tensorflow.python.keras.layers.core.Dense at 0x1114bd810>,
<tensorflow.python.keras.layers.core.Dense at 0x13a7035d0>,
<tensorflow.python.keras.layers.core.Dense at 0x13a6a9050>,
<tensorflow.python.keras.layers.core.Dense at 0x13a6a9bd0>,
<tensorflow.python.keras.layers.core.Dense at 0x107df4650>,
<tensorflow.python.keras.layers.core.Dense at 0x107e2b410>,
<tensorflow.python.keras.layers.core.Dense at 0x13a724910>,
<tensorflow.python.keras.layers.core.Dense at 0x13a6dd210>,
<tensorflow.python.keras.layers.core.Dense at 0x13e4b1b90>,
<tensorflow.python.keras.layers.core.Dense at 0x137080b10>,
<tensorflow.python.keras.layers.core.Dense at 0x13e4a1a10>,
<tensorflow.python.keras.layers.noise.AlphaDropout at 0x136ed69d0>,
<tensorflow.python.keras.layers.core.Dense at 0x1370af710>]
In[11]:
model.summary() #打印模型的结构
Out[8]:
Model: "sequential"
_________________________________________________________________
Layer (type) Output Shape Param #
=================================================================
flatten (Flatten) (None, 784) 0
_________________________________________________________________
dense (Dense) (None, 100) 78500
_________________________________________________________________
dense_1 (Dense) (None, 100) 10100
_________________________________________________________________
dense_2 (Dense) (None, 100) 10100
_________________________________________________________________
dense_3 (Dense) (None, 100) 10100
_________________________________________________________________
dense_4 (Dense) (None, 100) 10100
_________________________________________________________________
dense_5 (Dense) (None, 100) 10100
_________________________________________________________________
dense_6 (Dense) (None, 100) 10100
_________________________________________________________________
dense_7 (Dense) (None, 100) 10100
_________________________________________________________________
dense_8 (Dense) (None, 100) 10100
_________________________________________________________________
dense_9 (Dense) (None, 100) 10100
_________________________________________________________________
dense_10 (Dense) (None, 100) 10100
_________________________________________________________________
dense_11 (Dense) (None, 100) 10100
_________________________________________________________________
dense_12 (Dense) (None, 100) 10100
_________________________________________________________________
dense_13 (Dense) (None, 100) 10100
_________________________________________________________________
dense_14 (Dense) (None, 100) 10100
_________________________________________________________________
dense_15 (Dense) (None, 100) 10100
_________________________________________________________________
dense_16 (Dense) (None, 100) 10100
_________________________________________________________________
dense_17 (Dense) (None, 100) 10100
_________________________________________________________________
dense_18 (Dense) (None, 100) 10100
_________________________________________________________________
dense_19 (Dense) (None, 100) 10100
_________________________________________________________________
alpha_dropout (AlphaDropout) (None, 100) 0
_________________________________________________________________
dense_20 (Dense) (None, 10) 1010
=================================================================
Total params: 271,410
Trainable params: 271,410
Non-trainable params: 0
_________________________________________________________________
In[12]:
# 第一层 [None, 784] * w + b -> [None, 300] w.shape=[784,300], b=[300]
In[13]:
# TensorBoard,EarlyStopping,ModelCheckPoint
logdir='./dnn-selu-dropout-callbacks' # 设置一个文件夹路径
if not os.path.exists(logdir): # 若文件夹不存在，则创建文件夹
os.mkdir(logdir)
output_model_file=os.path.join(logdir,
'fashion_mnist_model.h5') #放入文件夹内，文件名fashion_mnist_model.h5
callbacks=[
keras.callbacks.TensorBoard(logdir),
keras.callbacks.ModelCheckpoint(output_model_file,
save_best_only=True), # 保存最好的模型，如果不是这个会默认保存最近的一个模型
keras.callbacks.EarlyStopping(patience=5,min_delta=1e-3)
]
history=model.fit(x_train_scaled,y_train,epochs=10,
validation_data=(x_valid_scaled,y_valid),
callbacks=callbacks)
Out[9]:
Train on 55000 samples, validate on 5000 samples
Epoch 1/10
55000/55000 [==============================] - 11s 195us/sample - loss: 0.6998 - accuracy: 0.7617 - val_loss: 0.5656 - val_accuracy: 0.8536
Epoch 2/10
55000/55000 [==============================] - 8s 144us/sample - loss: 0.4626 - accuracy: 0.8428 - val_loss: 0.6195 - val_accuracy: 0.8558
Epoch 3/10
55000/55000 [==============================] - 9s 162us/sample - loss: 0.4065 - accuracy: 0.8581 - val_loss: 0.5300 - val_accuracy: 0.8668
Epoch 4/10
55000/55000 [==============================] - 8s 142us/sample - loss: 0.3755 - accuracy: 0.8717 - val_loss: 0.6154 - val_accuracy: 0.8664
Epoch 5/10
55000/55000 [==============================] - 8s 152us/sample - loss: 0.3521 - accuracy: 0.8774 - val_loss: 0.5287 - val_accuracy: 0.8766
Epoch 6/10
55000/55000 [==============================] - 8s 153us/sample - loss: 0.3343 - accuracy: 0.8815 - val_loss: 0.4956 - val_accuracy: 0.8856
Epoch 7/10
55000/55000 [==============================] - 8s 143us/sample - loss: 0.3193 - accuracy: 0.8857 - val_loss: 0.5349 - val_accuracy: 0.8716
Epoch 8/10
55000/55000 [==============================] - 8s 144us/sample - loss: 0.3085 - accuracy: 0.8916 - val_loss: 0.5294 - val_accuracy: 0.8842
Epoch 9/10
55000/55000 [==============================] - 8s 145us/sample - loss: 0.2955 - accuracy: 0.8946 - val_loss: 0.4668 - val_accuracy: 0.8822
Epoch 10/10
55000/55000 [==============================] - 8s 152us/sample - loss: 0.2839 - accuracy: 0.8975 - val_loss: 0.4907 - val_accuracy: 0.8860
In[14]:
type(history)
Out[10]:
tensorflow.python.keras.callbacks.History
In[15]:
history.history
# 打印每次学习的结果
Out[11]:
{'loss': [0.6997782779043371,
0.4625766654621471,
0.4064591264659708,
0.37553091496554286,
0.35207060631621967,
0.3343261710730466,
0.3193407494176518,
0.30854321794509887,
0.29552189791636035,
0.28390346760099583],
'accuracy': [0.76165456,
0.84276366,
0.85809094,
0.8717273,
0.87743634,
0.8814909,
0.8856909,
0.89156365,
0.89461815,
0.8974909],
'val_loss': [0.5656432386219501,
0.6194551657661795,
0.5299783393919468,
0.6153697894215584,
0.5287225459891837,
0.49561948866695166,
0.5348633618405322,
0.5294362505242228,
0.4668049536377192,
0.4907300000913441],
'val_accuracy': [0.8536,
0.8558,
0.8668,
0.8664,
0.8766,
0.8856,
0.8716,
0.8842,
0.8822,
0.886]}
In[16]
def plot_learning_curves(history):
pd.DataFrame(history.history).plot(figsize=(8,5))
plt.grid(True)
plt.gca().set_ylim(0,1)
plt.show()
# 打印学习曲线
plot_learning_curves(history)
Out[12]:
In[17]:
model.evaluate(x_test_scaled,y_test) # 在测试集上验证
tensorflow.keras.model.evaluate
Out[13]:
10000/10000 [==============================] - 1s 95us/sample - loss: 0.5799 - accuracy: 0.8741
Out[14]:
[0.5799049034297467, 0.8741]
汇总：
#!/usr/bin/env python
# coding: utf-8
# In[1]:
import ssl
ssl._create_default_https_context = ssl._create_unverified_context
# 不知道为什么在本地的jupyter notebook上无法导入fashion_mnist数据集(本地需要，google colab不需要)
# In[23]:
import matplotlib as mpl
import matplotlib.pyplot as plt
get_ipython().run_line_magic('matplotlib', 'inline')
import numpy as np
import sklearn
import pandas as pd
import os
import sys
import time
import tensorflow as tf
from tensorflow import keras as keras
from sklearn.preprocessing import StandardScaler
for module in mpl,np,pd,sklearn,tf,keras:
print(module.__name__,module.__version__)
# 打印版本库
# In[3]:
fashion_mnist=keras.datasets.fashion_mnist
(x_train_all, y_train_all),(x_test, y_test)=fashion_mnist.load_data()
# 导入fashion_mnist数据集
# In[4]:
x_valid,x_train=x_train_all[:5000],x_train_all[5000:]
y_valid,y_train=y_train_all[:5000],y_train_all[5000:]
# fashion_mnist有6w个数据，前5k个为验证集，其中x为图片，y为序列号
print(x_valid.shape,y_valid.shape)
print(x_train.shape,y_valid.shape)
print(x_test.shape,y_test.shape)
# 打印数据集的格式
# In[5]:
print(np.max(x_train),np.min(x_train))
# 打印数据集中的最大值和最小值
# In[6]:
# x= (x-u)/std
scaler=StandardScaler()
# x_train:[None, 28, 28] -> [None, 784]
x_train_scaled=scaler.fit_transform(x_train.astype(np.float32).reshape(-1,1)).reshape(-1,28,28)
#会自动记录方差u和均值std，并进行归一化
x_valid_scaled=scaler.transform(x_valid.astype(np.float32).reshape(-1,1)).reshape(-1,28,28)
# 会根据自动记录的方差u和均值std进行归一化
x_test_scaled=scaler.transform(x_test.astype(np.float32).reshape(-1,1)).reshape(-1,28,28)
# 会根据自动记录的方差u和均值std进行归一化
# In[7]:
def show_single_image(img_arr):
plt.imshow(img_arr,cmap='binary')
plt.show()
# 打印单张图片
show_single_image(x_train[0])
# In[8]:
def show_images(n_rows,n_cols,x_data,y_data,class_names):
assert len(x_data)==len(y_data)
assert n_cols*n_rows<len(x_data)
plt.figure(figsize=(n_cols*1.4,n_rows*1.6))
for row in range(n_rows):
for col in range(n_cols):
index=n_cols*row+col
plt.subplot(n_rows,n_cols,index+1)
plt.imshow(x_data[index],cmap='binary',
interpolation='nearest')
plt.axis('off')
plt.title(class_names[y_data[index]])
plt.show()
# 打印n_rows行n_cols列的图片
class_names = ['T-shirt/top', 'Trouser', 'Pullover', 'Dress', 'Coat',
'Sandal', 'Shirt', 'Sneaker', 'Bag', 'Ankle boot']
# 所对应的名称
show_images(3,5,x_train,y_train,class_names)
# In[9]:
# 构建一个三层的神经网络
# model=keras.models.Sequential()
# model.add(keras.layers.Flatten(input_shape=[28,28])) # 展开成28*28的向量
# model.add(keras.layers.Dense(300,activation='relu')) # 全链接层，层数300，激活函数relu
# model.add(keras.layers.Dense(100,activation='relu'))
# model.add(keras.layers.Dense(10,activation='softmax')) # 有10个输出
# model=keras.models.Sequential([
# keras.layers.Flatten(input_shape=[28,28]),
# keras.layers.Dense(300,activation='relu'),
# keras.layers.Dense(100,activation='relu'),
# keras.layers.Dense(10,activation='softmax')
# ])
model=keras.models.Sequential()
model.add(keras.layers.Flatten(input_shape=[28,28]))
for _ in range(20):
model.add(keras.layers.Dense(100,activation='selu'))
# model.add(keras.layers.Dense(100,activation='relu'))
# model.add(keras.layers.BatchNormalization())
# 激活函数在前的后的批归一化
# model.add(keras.layers.Dense(100))
# model.add(keras.layers.BatchNormalization())
# model.add(keras.layers.Activation('relu'))
# model.add(keras.layers.Dropout(rate=0.5))
model.add(keras.layers.AlphaDropout(rate=0.5))
# AlphaDropout与Dropout的区别：1、均值方差不变 2、归一化性质不变
model.add(keras.layers.Dense(10,activation='softmax'))
# relu: y=max(0,x)
# softmax: 将向量变成概率分布 x=[x1,x2,x3]
# y=[e^x1/sum,e^x2/sum,e^x3/sum],sum=e^x1+e^x2+e^x3
# reason for sparse: y->index y->one_hot->[]
model.compile(loss='sparse_categorical_crossentropy',
optimizer='sgd',
metrics=['accuracy'])
# In[10]:
model.layers
# In[11]:
model.summary() #打印模型的结构
# In[12]:
# 第一层 [None, 784] * w + b -> [None, 300] w.shape=[784,300], b=[300]
# In[15]:
# TensorBoard,EarlyStopping,ModelCheckPoint
logdir='./dnn-selu-dropout-callbacks' # 设置一个文件夹路径
if not os.path.exists(logdir): # 若文件夹不存在，则创建文件夹
os.mkdir(logdir)
output_model_file=os.path.join(logdir,
'fashion_mnist_model.h5') #放入文件夹内，文件名fashion_mnist_model.h5
callbacks=[
keras.callbacks.TensorBoard(logdir),
keras.callbacks.ModelCheckpoint(output_model_file,
save_best_only=True), # 保存最好的模型，如果不是这个会默认保存最近的一个模型
keras.callbacks.EarlyStopping(patience=5,min_delta=1e-3)
]
history=model.fit(x_train_scaled,y_train,epochs=10,
validation_data=(x_valid_scaled,y_valid),
callbacks=callbacks)
# In[16]:
type(history)
# In[17]:
history.history
# 打印每次学习的结果
# In[18]:
def plot_learning_curves(history):
pd.DataFrame(history.history).plot(figsize=(8,5))
plt.grid(True)
plt.gca().set_ylim(0,1)
plt.show()
# 打印学习曲线
plot_learning_curves(history)
# In[19]:
model.evaluate(x_test_scaled,y_test) # 在测试集上验证
