企业网站主页模版,美图秀秀在线制作图片,小程序平台取名,建设银行网站支付流程文章目录 一、前言二、前期工作1. 设置GPU#xff08;如果使用的是CPU可以忽略这步#xff09;2. 导入数据3. 查看数据4.标签数字化 二、构建一个tf.data.Dataset1.预处理函数2.加载数据3.配置数据 三、搭建网络模型四、编译五、训练六、模型评估七、保存和加载模型八、预测 … 文章目录 一、前言二、前期工作1. 设置GPU如果使用的是CPU可以忽略这步2. 导入数据3. 查看数据4.标签数字化 二、构建一个tf.data.Dataset1.预处理函数2.加载数据3.配置数据 三、搭建网络模型四、编译五、训练六、模型评估七、保存和加载模型八、预测 一、前言
我的环境
语言环境Python3.6.5编译器jupyter notebook深度学习环境TensorFlow2.4.1
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卷积神经网络CNN实现mnist手写数字识别 卷积神经网络CNN多种图片分类的实现卷积神经网络CNN衣服图像分类的实现卷积神经网络CNN鲜花识别卷积神经网络CNN天气识别 卷积神经网络VGG-16识别海贼王草帽一伙卷积神经网络ResNet-50鸟类识别 卷积神经网络AlexNet鸟类识别
来自专栏机器学习与深度学习算法推荐
二、前期工作
1. 设置GPU如果使用的是CPU可以忽略这步
import tensorflow as tfgpus tf.config.list_physical_devices(GPU)if gpus:tf.config.experimental.set_memory_growth(gpus[0], True) #设置GPU显存用量按需使用tf.config.set_visible_devices([gpus[0]],GPU)2. 导入数据
import matplotlib.pyplot as plt
# 支持中文
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import os,PIL,random,pathlib# 设置随机种子尽可能使结果可以重现
import numpy as np
np.random.seed(1)# 设置随机种子尽可能使结果可以重现
import tensorflow as tf
tf.random.set_seed(1)data_dir code
data_dir pathlib.Path(data_dir)all_image_paths list(data_dir.glob(*))
all_image_paths [str(path) for path in all_image_paths]# 打乱数据
random.shuffle(all_image_paths)# 获取数据标签
all_label_names [path.split(\\)[5].split(.)[0] for path in all_image_paths]image_count len(all_image_paths)
print(图片总数为,image_count)3. 查看数据
plt.figure(figsize(10,5))for i in range(20):plt.subplot(5,4,i1)plt.xticks([])plt.yticks([])plt.grid(False)# 显示图片images plt.imread(all_image_paths[i])plt.imshow(images)# 显示标签plt.xlabel(all_label_names[i])plt.show()4.标签数字化
number [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
alphabet [a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z]
char_set number alphabet
char_set_len len(char_set)
label_name_len len(all_label_names[0])# 将字符串数字化
def text2vec(text):vector np.zeros([label_name_len, char_set_len])for i, c in enumerate(text):idx char_set.index(c)vector[i][idx] 1.0return vectorall_labels [text2vec(i) for i in all_label_names]二、构建一个tf.data.Dataset
1.预处理函数
def preprocess_image(image):image tf.image.decode_jpeg(image, channels1)image tf.image.resize(image, [50, 200])return image/255.0def load_and_preprocess_image(path):image tf.io.read_file(path)return preprocess_image(image)2.加载数据
构建 tf.data.Dataset 最简单的方法就是使用 from_tensor_slices 方法。
AUTOTUNE tf.data.experimental.AUTOTUNEpath_ds tf.data.Dataset.from_tensor_slices(all_image_paths)
image_ds path_ds.map(load_and_preprocess_image, num_parallel_callsAUTOTUNE)
label_ds tf.data.Dataset.from_tensor_slices(all_labels)image_label_ds tf.data.Dataset.zip((image_ds, label_ds))
image_label_dsZipDataset shapes: ((50, 200, 1), (5, 36)), types: (tf.float32, tf.float64)train_ds image_label_ds.take(1000) # 前1000个batch
val_ds image_label_ds.skip(1000) # 跳过前1000选取后面的3.配置数据
先复习一下prefetch()函数。prefetch()功能详细介绍CPU 正在准备数据时加速器处于空闲状态。相反当加速器正在训练模型时CPU 处于空闲状态。因此训练所用的时间是 CPU 预处理时间和加速器训练时间的总和。prefetch()将训练步骤的预处理和模型执行过程重叠到一起。当加速器正在执行第 N 个训练步时CPU 正在准备第 N1 步的数据。这样做不仅可以最大限度地缩短训练的单步用时而不是总用时而且可以缩短提取和转换数据所需的时间。如果不使用prefetch()CPU 和 GPU/TPU 在大部分时间都处于空闲状态
BATCH_SIZE 16train_ds train_ds.batch(BATCH_SIZE)
train_ds train_ds.prefetch(buffer_sizeAUTOTUNE)val_ds val_ds.batch(BATCH_SIZE)
val_ds val_ds.prefetch(buffer_sizeAUTOTUNE)
val_ds三、搭建网络模型
from tensorflow.keras import datasets, layers, modelsmodel models.Sequential([layers.Conv2D(32, (3, 3), activationrelu, input_shape(50, 200, 1)),#卷积层1卷积核3*3layers.MaxPooling2D((2, 2)), #池化层12*2采样layers.Conv2D(64, (3, 3), activationrelu), #卷积层2卷积核3*3layers.MaxPooling2D((2, 2)), #池化层22*2采样layers.Flatten(), #Flatten层连接卷积层与全连接层layers.Dense(1000, activationrelu), #全连接层特征进一步提取layers.Dense(label_name_len * char_set_len),layers.Reshape([label_name_len, char_set_len]),layers.Softmax() #输出层输出预期结果
])
# 打印网络结构
model.summary()Model: sequential
_________________________________________________________________
Layer (type) Output Shape Param # conv2d (Conv2D) (None, 48, 198, 32) 320
_________________________________________________________________
max_pooling2d (MaxPooling2D) (None, 24, 99, 32) 0
_________________________________________________________________
conv2d_1 (Conv2D) (None, 22, 97, 64) 18496
_________________________________________________________________
max_pooling2d_1 (MaxPooling2 (None, 11, 48, 64) 0
_________________________________________________________________
flatten (Flatten) (None, 33792) 0
_________________________________________________________________
dense (Dense) (None, 1000) 33793000
_________________________________________________________________
dense_1 (Dense) (None, 180) 180180
_________________________________________________________________
reshape (Reshape) (None, 5, 36) 0
_________________________________________________________________
softmax (Softmax) (None, 5, 36) 0 Total params: 33,991,996
Trainable params: 33,991,996
Non-trainable params: 0
_________________________________________________________________四、编译
model.compile(optimizeradam,losscategorical_crossentropy,metrics[accuracy])五、训练
epochs 20history model.fit(train_ds,validation_dataval_ds,epochsepochs
)Epoch 1/20
63/63 [] - 4s 21ms/step - loss: 3.2998 - accuracy: 0.0934 - val_loss: 2.2876 - val_accuracy: 0.2943
Epoch 2/20
63/63 [] - 1s 9ms/step - loss: 1.7016 - accuracy: 0.5195 - val_loss: 1.2014 - val_accuracy: 0.6314
Epoch 3/20
63/63 [] - 1s 10ms/step - loss: 0.5267 - accuracy: 0.8379 - val_loss: 0.9039 - val_accuracy: 0.7286
Epoch 4/20
63/63 [] - 1s 10ms/step - loss: 0.1911 - accuracy: 0.9442 - val_loss: 0.8609 - val_accuracy: 0.7457
Epoch 5/20
63/63 [] - 1s 10ms/step - loss: 0.0916 - accuracy: 0.9714 - val_loss: 0.8937 - val_accuracy: 0.7886
Epoch 6/20
63/63 [] - 1s 10ms/step - loss: 0.0680 - accuracy: 0.9798 - val_loss: 0.5842 - val_accuracy: 0.8429
Epoch 7/20
63/63 [] - 1s 10ms/step - loss: 0.0443 - accuracy: 0.9900 - val_loss: 0.6235 - val_accuracy: 0.8200
Epoch 8/20
63/63 [] - 1s 10ms/step - loss: 0.0203 - accuracy: 0.9947 - val_loss: 0.7697 - val_accuracy: 0.8029
Epoch 9/20
63/63 [] - 1s 10ms/step - loss: 0.0131 - accuracy: 0.9975 - val_loss: 0.6660 - val_accuracy: 0.8314
Epoch 10/20
63/63 [] - 1s 10ms/step - loss: 0.0227 - accuracy: 0.9940 - val_loss: 0.6018 - val_accuracy: 0.8229
Epoch 11/20
63/63 [] - 1s 10ms/step - loss: 0.0093 - accuracy: 0.9985 - val_loss: 0.5714 - val_accuracy: 0.8429
Epoch 12/20
63/63 [] - 1s 10ms/step - loss: 0.0010 - accuracy: 1.0000 - val_loss: 0.5793 - val_accuracy: 0.8571
Epoch 13/20
63/63 [] - 1s 10ms/step - loss: 2.6284e-04 - accuracy: 1.0000 - val_loss: 0.5920 - val_accuracy: 0.8571
Epoch 14/20
63/63 [] - 1s 10ms/step - loss: 1.8502e-04 - accuracy: 1.0000 - val_loss: 0.6031 - val_accuracy: 0.8571
Epoch 15/20
63/63 [] - 1s 10ms/step - loss: 1.4164e-04 - accuracy: 1.0000 - val_loss: 0.6120 - val_accuracy: 0.8571
Epoch 16/20
63/63 [] - 1s 10ms/step - loss: 1.1334e-04 - accuracy: 1.0000 - val_loss: 0.6198 - val_accuracy: 0.8571
Epoch 17/20
63/63 [] - 1s 10ms/step - loss: 9.4027e-05 - accuracy: 1.0000 - val_loss: 0.6269 - val_accuracy: 0.8571
Epoch 18/20
63/63 [] - 1s 10ms/step - loss: 8.0025e-05 - accuracy: 1.0000 - val_loss: 0.6335 - val_accuracy: 0.8514
Epoch 19/20
63/63 [] - 1s 9ms/step - loss: 6.9294e-05 - accuracy: 1.0000 - val_loss: 0.6396 - val_accuracy: 0.8486
Epoch 20/20
63/63 [] - 1s 10ms/step - loss: 6.0775e-05 - accuracy: 1.0000 - val_loss: 0.6448 - val_accuracy: 0.8486六、模型评估
acc history.history[accuracy]
val_acc history.history[val_accuracy]loss history.history[loss]
val_loss history.history[val_loss]epochs_range range(epochs)plt.figure(figsize(12, 4))
plt.subplot(1, 2, 1)plt.plot(epochs_range, acc, labelTraining Accuracy)
plt.plot(epochs_range, val_acc, labelValidation Accuracy)
plt.legend(loclower right)
plt.title(Training and Validation Accuracy)plt.subplot(1, 2, 2)
plt.plot(epochs_range, loss, labelTraining Loss)
plt.plot(epochs_range, val_loss, labelValidation Loss)
plt.legend(locupper right)
plt.title(Training and Validation Loss)
plt.show()七、保存和加载模型
# 保存模型
model.save(model/12_model.h5)# 加载模型
new_model tf.keras.models.load_model(model/12_model.h5)八、预测
def vec2text(vec):还原标签向量-字符串text []for i, c in enumerate(vec):text.append(char_set[c])return .join(text)plt.figure(figsize(10, 8)) # 图形的宽为10高为8for images, labels in val_ds.take(1):for i in range(6):ax plt.subplot(5, 2, i 1) # 显示图片plt.imshow(images[i])# 需要给图片增加一个维度img_array tf.expand_dims(images[i], 0) # 使用模型预测验证码predictions model.predict(img_array)plt.title(vec2text(np.argmax(predictions, axis2)[0]))plt.axis(off)
