J1 ResNet-50算法实战与解析

 一、理论知识储备

1. 残差网络的由来

ResNet主要解决了CNN在深度加深时的退化问题(梯度消失与梯度爆炸)。 虽然BN可以在一定程度上保持梯度的大小稳定,但当层级数加大时不但不容易收敛,还容易出现准确率饱和并迅速下降,这一下降由网络过于复杂导致。

ResNet有一个额外的分支把输入直接连在输出上,使输出为分支输出+卷积输出,通过人为制造恒等映射使整个网络朝恒等映射的方向去收敛。

复杂网络通用规则:如果一个网络通过简单的手工设置参数值就可以达到想要的结果,那这种结构很容易通过训练来收敛到该结果

较浅的ResNet网络(左):两层残差单元包含两个相同输出通道数的3x3卷积。

较深的ResNet网络(右):先用1x1卷积进行降维,然后3x3卷积,最后用1x1升维恢复原有维度,又称bottleneck结构。

2. ResNet50

包含两个基本块:Conv Block和Identity Block

二、前期准备

1. 导入数据

import matplotlib.pyplot as plt
# set the font to SimHei to display Chinese characters
plt.rcParams['font.sans-serif'] = ['SimHei']  
plt.rcParams['axes.unicode_minus'] = False  

import os, PIL, pathlib
import numpy as np

from tensorflow import keras
from tensorflow.keras import layers,models

data_dir = 'C:/Self_Learning/Deep_Learning/K_Codes/data/8_data/bird_photos/'
data_dir = pathlib.Path(data_dir)

 2. 查看数据

# Check the data
image_count = len(list(data_dir.glob('*/*.jpg')))
print('Total images:', image_count)

三、数据预处理

1. 加载数据

# Load the data
batch_size = 8
img_height = 224
img_width = 224

train_ds = keras.preprocessing.image_dataset_from_directory(
    data_dir,
    validation_split=0.2,
    subset='training',
    seed=123,
    image_size=(img_height, img_width),
    batch_size=batch_size)

val_ds = keras.preprocessing.image_dataset_from_directory(
    data_dir,
    validation_split=0.2,
    subset='validation',
    seed=123,
    image_size=(img_height, img_width),
    batch_size=batch_size)

# Check the class names
class_names = train_ds.class_names
print(class_names)

 2. 数据可视化

# Visualize the data
plt.figure(figsize=(10, 5))

for images, labels in train_ds.take(1):
    for i in range(8):
        ax = plt.subplot(2, 4, i + 1)

        image = images[i].numpy().astype("uint8")
        plt.imshow(image)
        plt.title(class_names[labels[i]])
        plt.axis("off")
    plt.show()

 3. 检查数据

# Check the data shape
for image_batch, labels_batch in train_ds:
    print(image_batch.shape)
    print(labels_batch.shape)
    break

  4. 配置数据集

AUTOTUNE = tf.data.AUTOTUNE
train_ds = train_ds.cache().shuffle(1000).prefetch(buffer_size=AUTOTUNE)
val_ds = val_ds.cache().prefetch(buffer_size=AUTOTUNE)

四、训练模型 

1. 构建ResNet-50模型

# Define the ResNet50 model

def identity_block(input_tensor, kernel_size, filters, stage, block):
    filters1, filters2, filters3 = filters

    name_base = str(stage) + block + '_identity_block_'

    x = Conv2D(filters1, (1, 1), name=name_base + 'conv1')(input_tensor)
    x = BatchNormalization(name=name_base + 'bn1')(x)
    x = Activation('relu', name=name_base + 'relu1')(x)

    x = Conv2D(filters2, kernel_size, padding='same', name=name_base + 'conv2')(x)
    x = BatchNormalization(name=name_base + 'bn2')(x)
    x = Activation('relu', name=name_base + 'relu2')(x)

    x = Conv2D(filters3, (1, 1), name=name_base + 'conv3')(x)
    x = BatchNormalization(name=name_base + 'bn3')(x)

    x = layers.add([x, input_tensor], name=name_base + 'add')
    x = Activation('relu', name=name_base + 'relu4')(x)

    return x

def conv_block(input_tensor, kernel_size, filters, stage, block, strides=(2, 2)):
    filters1, filters2, filters3 = filters

    res_name_base = str(stage) + block + '_conv_block_res_'
    name_base = str(stage) + block + '_conv_block_'

    x = Conv2D(filters1, (1, 1), strides=strides, name=name_base + 'conv1')(input_tensor)
    x = BatchNormalization(name=name_base + 'bn1')(x)
    x = Activation('relu', name=name_base + 'relu1')(x)

    x = Conv2D(filters2, kernel_size, padding='same', name=name_base + 'conv2')(x)
    x = BatchNormalization(name=name_base + 'bn2')(x)
    x = Activation('relu', name=name_base + 'relu2')(x)

    x = Conv2D(filters3, (1, 1), name=name_base + 'conv3')(x)
    x = BatchNormalization(name=name_base + 'bn3')(x)

    shortcut = Conv2D(filters3, (1, 1), strides=strides, name=res_name_base + 'conv')(input_tensor)
    shortcut = BatchNormalization(name=res_name_base + 'bn')(shortcut)

    x = layers.add([x, shortcut], name=name_base + 'add')
    x = Activation('relu', name=name_base + 'relu4')(x)

    return x

def ResNet50(input_shape=(224, 224, 3), classes=1000):

    img_input = Input(shape=input_shape)
    x = ZeroPadding2D((3, 3))(img_input)

    x = Conv2D(64, (7, 7), strides=(2, 2), name='conv1')(x)
    x = BatchNormalization(name='bn_conv1')(x)
    x = Activation('relu')(x)
    x = MaxPooling2D((3, 3), strides=(2, 2))(x)

    x = conv_block(x, 3, [64, 64, 256], stage=2, block='a', strides=(1, 1))
    x = identity_block(x, 3, [64, 64, 256], stage=2, block='b')
    x = identity_block(x, 3, [64, 64, 256], stage=2, block='c')

    x = conv_block(x, 3, [128, 128, 512], stage=3, block='a')
    x = identity_block(x, 3, [128, 128, 512], stage=3, block='b')
    x = identity_block(x, 3, [128, 128, 512], stage=3, block='c')
    x = identity_block(x, 3, [128, 128, 512], stage=3, block='d')

    x = conv_block(x, 3, [256, 256, 1024], stage=4, block='a')
    x = identity_block(x, 3, [256, 256, 1024], stage=4, block='b')
    x = identity_block(x, 3, [256, 256, 1024], stage=4, block='c')
    x = identity_block(x, 3, [256, 256, 1024], stage=4, block='d')
    x = identity_block(x, 3, [256, 256, 1024], stage=4, block='e')
    x = identity_block(x, 3, [256, 256, 1024], stage=4, block='f')

    x = conv_block(x, 3, [512, 512, 2048], stage=5, block='a')
    x = identity_block(x, 3, [512, 512, 2048], stage=5, block='b')
    x = identity_block(x, 3, [512, 512, 2048], stage=5, block='c')

    x = AveragePooling2D((7, 7), name='avg_pool')(x)

    x = Flatten()(x)
    x = Dense(classes, activation='softmax', name='fc1000')(x)

    model = Model(img_input, x, name='ResNet50')

    model.load_weights('C:/Self_Learning/Deep_Learning/K_Codes/data/8_data/ResNet50_weights_tf_dim_ordering_tf_kernels.h5', by_name=True, skip_mismatch=True)

    return model

model = ResNet50()
model.summary()
Model: "ResNet50"
__________________________________________________________________________________________________
 Layer (type)                Output Shape                 Param #   Connected to                  
==================================================================================================
 input_3 (InputLayer)        [(None, 224, 224, 3)]        0         []                            
                                                                                                  
 zero_padding2d_2 (ZeroPadd  (None, 230, 230, 3)          0         ['input_3[0][0]']             
 ing2D)                                                                                           
                                                                                                  
 conv1 (Conv2D)              (None, 112, 112, 64)         9472      ['zero_padding2d_2[0][0]']    
                                                                                                  
 bn_conv1 (BatchNormalizati  (None, 112, 112, 64)         256       ['conv1[0][0]']               
 on)                                                                                              
                                                                                                  
 activation_4 (Activation)   (None, 112, 112, 64)         0         ['bn_conv1[0][0]']            
                                                                                                  
 max_pooling2d_2 (MaxPoolin  (None, 55, 55, 64)           0         ['activation_4[0][0]']        
 g2D)                                                                                             
                                                                                                  
 2a_conv_block_conv1 (Conv2  (None, 55, 55, 64)           4160      ['max_pooling2d_2[0][0]']     
 D)                                                                                               
                                                                                                  
 2a_conv_block_bn1 (BatchNo  (None, 55, 55, 64)           256       ['2a_conv_block_conv1[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 2a_conv_block_relu1 (Activ  (None, 55, 55, 64)           0         ['2a_conv_block_bn1[0][0]']   
 ation)                                                                                           
                                                                                                  
 2a_conv_block_conv2 (Conv2  (None, 55, 55, 64)           36928     ['2a_conv_block_relu1[0][0]'] 
 D)                                                                                               
                                                                                                  
 2a_conv_block_bn2 (BatchNo  (None, 55, 55, 64)           256       ['2a_conv_block_conv2[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 2a_conv_block_relu2 (Activ  (None, 55, 55, 64)           0         ['2a_conv_block_bn2[0][0]']   
 ation)                                                                                           
                                                                                                  
 2a_conv_block_conv3 (Conv2  (None, 55, 55, 256)          16640     ['2a_conv_block_relu2[0][0]'] 
 D)                                                                                               
                                                                                                  
 2a_conv_block_res_conv (Co  (None, 55, 55, 256)          16640     ['max_pooling2d_2[0][0]']     
 nv2D)                                                                                            
                                                                                                  
 2a_conv_block_bn3 (BatchNo  (None, 55, 55, 256)          1024      ['2a_conv_block_conv3[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 2a_conv_block_res_bn (Batc  (None, 55, 55, 256)          1024      ['2a_conv_block_res_conv[0][0]
 hNormalization)                                                    ']                            
                                                                                                  
 2a_conv_block_add (Add)     (None, 55, 55, 256)          0         ['2a_conv_block_bn3[0][0]',   
                                                                     '2a_conv_block_res_bn[0][0]']
                                                                                                  
 2a_conv_block_relu4 (Activ  (None, 55, 55, 256)          0         ['2a_conv_block_add[0][0]']   
 ation)                                                                                           
                                                                                                  
 2b_identity_block_conv1 (C  (None, 55, 55, 64)           16448     ['2a_conv_block_relu4[0][0]'] 
 onv2D)                                                                                           
                                                                                                  
 2b_identity_block_bn1 (Bat  (None, 55, 55, 64)           256       ['2b_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 2b_identity_block_relu1 (A  (None, 55, 55, 64)           0         ['2b_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 2b_identity_block_conv2 (C  (None, 55, 55, 64)           36928     ['2b_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 2b_identity_block_bn2 (Bat  (None, 55, 55, 64)           256       ['2b_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 2b_identity_block_relu2 (A  (None, 55, 55, 64)           0         ['2b_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 2b_identity_block_conv3 (C  (None, 55, 55, 256)          16640     ['2b_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 2b_identity_block_bn3 (Bat  (None, 55, 55, 256)          1024      ['2b_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 2b_identity_block_add (Add  (None, 55, 55, 256)          0         ['2b_identity_block_bn3[0][0]'
 )                                                                  , '2a_conv_block_relu4[0][0]']
                                                                                                  
 2b_identity_block_relu4 (A  (None, 55, 55, 256)          0         ['2b_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 2c_identity_block_conv1 (C  (None, 55, 55, 64)           16448     ['2b_identity_block_relu4[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 2c_identity_block_bn1 (Bat  (None, 55, 55, 64)           256       ['2c_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 2c_identity_block_relu1 (A  (None, 55, 55, 64)           0         ['2c_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 2c_identity_block_conv2 (C  (None, 55, 55, 64)           36928     ['2c_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 2c_identity_block_bn2 (Bat  (None, 55, 55, 64)           256       ['2c_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 2c_identity_block_relu2 (A  (None, 55, 55, 64)           0         ['2c_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 2c_identity_block_conv3 (C  (None, 55, 55, 256)          16640     ['2c_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 2c_identity_block_bn3 (Bat  (None, 55, 55, 256)          1024      ['2c_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 2c_identity_block_add (Add  (None, 55, 55, 256)          0         ['2c_identity_block_bn3[0][0]'
 )                                                                  , '2b_identity_block_relu4[0][
                                                                    0]']                          
                                                                                                  
 2c_identity_block_relu4 (A  (None, 55, 55, 256)          0         ['2c_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3a_conv_block_conv1 (Conv2  (None, 28, 28, 128)          32896     ['2c_identity_block_relu4[0][0
 D)                                                                 ]']                           
                                                                                                  
 3a_conv_block_bn1 (BatchNo  (None, 28, 28, 128)          512       ['3a_conv_block_conv1[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 3a_conv_block_relu1 (Activ  (None, 28, 28, 128)          0         ['3a_conv_block_bn1[0][0]']   
 ation)                                                                                           
                                                                                                  
 3a_conv_block_conv2 (Conv2  (None, 28, 28, 128)          147584    ['3a_conv_block_relu1[0][0]'] 
 D)                                                                                               
                                                                                                  
 3a_conv_block_bn2 (BatchNo  (None, 28, 28, 128)          512       ['3a_conv_block_conv2[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 3a_conv_block_relu2 (Activ  (None, 28, 28, 128)          0         ['3a_conv_block_bn2[0][0]']   
 ation)                                                                                           
                                                                                                  
 3a_conv_block_conv3 (Conv2  (None, 28, 28, 512)          66048     ['3a_conv_block_relu2[0][0]'] 
 D)                                                                                               
                                                                                                  
 3a_conv_block_res_conv (Co  (None, 28, 28, 512)          131584    ['2c_identity_block_relu4[0][0
 nv2D)                                                              ]']                           
                                                                                                  
 3a_conv_block_bn3 (BatchNo  (None, 28, 28, 512)          2048      ['3a_conv_block_conv3[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 3a_conv_block_res_bn (Batc  (None, 28, 28, 512)          2048      ['3a_conv_block_res_conv[0][0]
 hNormalization)                                                    ']                            
                                                                                                  
 3a_conv_block_add (Add)     (None, 28, 28, 512)          0         ['3a_conv_block_bn3[0][0]',   
                                                                     '3a_conv_block_res_bn[0][0]']
                                                                                                  
 3a_conv_block_relu4 (Activ  (None, 28, 28, 512)          0         ['3a_conv_block_add[0][0]']   
 ation)                                                                                           
                                                                                                  
 3b_identity_block_conv1 (C  (None, 28, 28, 128)          65664     ['3a_conv_block_relu4[0][0]'] 
 onv2D)                                                                                           
                                                                                                  
 3b_identity_block_bn1 (Bat  (None, 28, 28, 128)          512       ['3b_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3b_identity_block_relu1 (A  (None, 28, 28, 128)          0         ['3b_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3b_identity_block_conv2 (C  (None, 28, 28, 128)          147584    ['3b_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 3b_identity_block_bn2 (Bat  (None, 28, 28, 128)          512       ['3b_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3b_identity_block_relu2 (A  (None, 28, 28, 128)          0         ['3b_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3b_identity_block_conv3 (C  (None, 28, 28, 512)          66048     ['3b_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 3b_identity_block_bn3 (Bat  (None, 28, 28, 512)          2048      ['3b_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3b_identity_block_add (Add  (None, 28, 28, 512)          0         ['3b_identity_block_bn3[0][0]'
 )                                                                  , '3a_conv_block_relu4[0][0]']
                                                                                                  
 3b_identity_block_relu4 (A  (None, 28, 28, 512)          0         ['3b_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3c_identity_block_conv1 (C  (None, 28, 28, 128)          65664     ['3b_identity_block_relu4[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 3c_identity_block_bn1 (Bat  (None, 28, 28, 128)          512       ['3c_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3c_identity_block_relu1 (A  (None, 28, 28, 128)          0         ['3c_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3c_identity_block_conv2 (C  (None, 28, 28, 128)          147584    ['3c_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 3c_identity_block_bn2 (Bat  (None, 28, 28, 128)          512       ['3c_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3c_identity_block_relu2 (A  (None, 28, 28, 128)          0         ['3c_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3c_identity_block_conv3 (C  (None, 28, 28, 512)          66048     ['3c_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 3c_identity_block_bn3 (Bat  (None, 28, 28, 512)          2048      ['3c_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3c_identity_block_add (Add  (None, 28, 28, 512)          0         ['3c_identity_block_bn3[0][0]'
 )                                                                  , '3b_identity_block_relu4[0][
                                                                    0]']                          
                                                                                                  
 3c_identity_block_relu4 (A  (None, 28, 28, 512)          0         ['3c_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3d_identity_block_conv1 (C  (None, 28, 28, 128)          65664     ['3c_identity_block_relu4[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 3d_identity_block_bn1 (Bat  (None, 28, 28, 128)          512       ['3d_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3d_identity_block_relu1 (A  (None, 28, 28, 128)          0         ['3d_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3d_identity_block_conv2 (C  (None, 28, 28, 128)          147584    ['3d_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 3d_identity_block_bn2 (Bat  (None, 28, 28, 128)          512       ['3d_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3d_identity_block_relu2 (A  (None, 28, 28, 128)          0         ['3d_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 3d_identity_block_conv3 (C  (None, 28, 28, 512)          66048     ['3d_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 3d_identity_block_bn3 (Bat  (None, 28, 28, 512)          2048      ['3d_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 3d_identity_block_add (Add  (None, 28, 28, 512)          0         ['3d_identity_block_bn3[0][0]'
 )                                                                  , '3c_identity_block_relu4[0][
                                                                    0]']                          
                                                                                                  
 3d_identity_block_relu4 (A  (None, 28, 28, 512)          0         ['3d_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4a_conv_block_conv1 (Conv2  (None, 14, 14, 256)          131328    ['3d_identity_block_relu4[0][0
 D)                                                                 ]']                           
                                                                                                  
 4a_conv_block_bn1 (BatchNo  (None, 14, 14, 256)          1024      ['4a_conv_block_conv1[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 4a_conv_block_relu1 (Activ  (None, 14, 14, 256)          0         ['4a_conv_block_bn1[0][0]']   
 ation)                                                                                           
                                                                                                  
 4a_conv_block_conv2 (Conv2  (None, 14, 14, 256)          590080    ['4a_conv_block_relu1[0][0]'] 
 D)                                                                                               
                                                                                                  
 4a_conv_block_bn2 (BatchNo  (None, 14, 14, 256)          1024      ['4a_conv_block_conv2[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 4a_conv_block_relu2 (Activ  (None, 14, 14, 256)          0         ['4a_conv_block_bn2[0][0]']   
 ation)                                                                                           
                                                                                                  
 4a_conv_block_conv3 (Conv2  (None, 14, 14, 1024)         263168    ['4a_conv_block_relu2[0][0]'] 
 D)                                                                                               
                                                                                                  
 4a_conv_block_res_conv (Co  (None, 14, 14, 1024)         525312    ['3d_identity_block_relu4[0][0
 nv2D)                                                              ]']                           
                                                                                                  
 4a_conv_block_bn3 (BatchNo  (None, 14, 14, 1024)         4096      ['4a_conv_block_conv3[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 4a_conv_block_res_bn (Batc  (None, 14, 14, 1024)         4096      ['4a_conv_block_res_conv[0][0]
 hNormalization)                                                    ']                            
                                                                                                  
 4a_conv_block_add (Add)     (None, 14, 14, 1024)         0         ['4a_conv_block_bn3[0][0]',   
                                                                     '4a_conv_block_res_bn[0][0]']
                                                                                                  
 4a_conv_block_relu4 (Activ  (None, 14, 14, 1024)         0         ['4a_conv_block_add[0][0]']   
 ation)                                                                                           
                                                                                                  
 4b_identity_block_conv1 (C  (None, 14, 14, 256)          262400    ['4a_conv_block_relu4[0][0]'] 
 onv2D)                                                                                           
                                                                                                  
 4b_identity_block_bn1 (Bat  (None, 14, 14, 256)          1024      ['4b_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4b_identity_block_relu1 (A  (None, 14, 14, 256)          0         ['4b_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4b_identity_block_conv2 (C  (None, 14, 14, 256)          590080    ['4b_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4b_identity_block_bn2 (Bat  (None, 14, 14, 256)          1024      ['4b_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4b_identity_block_relu2 (A  (None, 14, 14, 256)          0         ['4b_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4b_identity_block_conv3 (C  (None, 14, 14, 1024)         263168    ['4b_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4b_identity_block_bn3 (Bat  (None, 14, 14, 1024)         4096      ['4b_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4b_identity_block_add (Add  (None, 14, 14, 1024)         0         ['4b_identity_block_bn3[0][0]'
 )                                                                  , '4a_conv_block_relu4[0][0]']
                                                                                                  
 4b_identity_block_relu4 (A  (None, 14, 14, 1024)         0         ['4b_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4c_identity_block_conv1 (C  (None, 14, 14, 256)          262400    ['4b_identity_block_relu4[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4c_identity_block_bn1 (Bat  (None, 14, 14, 256)          1024      ['4c_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4c_identity_block_relu1 (A  (None, 14, 14, 256)          0         ['4c_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4c_identity_block_conv2 (C  (None, 14, 14, 256)          590080    ['4c_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4c_identity_block_bn2 (Bat  (None, 14, 14, 256)          1024      ['4c_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4c_identity_block_relu2 (A  (None, 14, 14, 256)          0         ['4c_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4c_identity_block_conv3 (C  (None, 14, 14, 1024)         263168    ['4c_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4c_identity_block_bn3 (Bat  (None, 14, 14, 1024)         4096      ['4c_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4c_identity_block_add (Add  (None, 14, 14, 1024)         0         ['4c_identity_block_bn3[0][0]'
 )                                                                  , '4b_identity_block_relu4[0][
                                                                    0]']                          
                                                                                                  
 4c_identity_block_relu4 (A  (None, 14, 14, 1024)         0         ['4c_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4d_identity_block_conv1 (C  (None, 14, 14, 256)          262400    ['4c_identity_block_relu4[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4d_identity_block_bn1 (Bat  (None, 14, 14, 256)          1024      ['4d_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4d_identity_block_relu1 (A  (None, 14, 14, 256)          0         ['4d_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4d_identity_block_conv2 (C  (None, 14, 14, 256)          590080    ['4d_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4d_identity_block_bn2 (Bat  (None, 14, 14, 256)          1024      ['4d_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4d_identity_block_relu2 (A  (None, 14, 14, 256)          0         ['4d_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4d_identity_block_conv3 (C  (None, 14, 14, 1024)         263168    ['4d_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4d_identity_block_bn3 (Bat  (None, 14, 14, 1024)         4096      ['4d_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4d_identity_block_add (Add  (None, 14, 14, 1024)         0         ['4d_identity_block_bn3[0][0]'
 )                                                                  , '4c_identity_block_relu4[0][
                                                                    0]']                          
                                                                                                  
 4d_identity_block_relu4 (A  (None, 14, 14, 1024)         0         ['4d_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4e_identity_block_conv1 (C  (None, 14, 14, 256)          262400    ['4d_identity_block_relu4[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4e_identity_block_bn1 (Bat  (None, 14, 14, 256)          1024      ['4e_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4e_identity_block_relu1 (A  (None, 14, 14, 256)          0         ['4e_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4e_identity_block_conv2 (C  (None, 14, 14, 256)          590080    ['4e_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4e_identity_block_bn2 (Bat  (None, 14, 14, 256)          1024      ['4e_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4e_identity_block_relu2 (A  (None, 14, 14, 256)          0         ['4e_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4e_identity_block_conv3 (C  (None, 14, 14, 1024)         263168    ['4e_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4e_identity_block_bn3 (Bat  (None, 14, 14, 1024)         4096      ['4e_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4e_identity_block_add (Add  (None, 14, 14, 1024)         0         ['4e_identity_block_bn3[0][0]'
 )                                                                  , '4d_identity_block_relu4[0][
                                                                    0]']                          
                                                                                                  
 4e_identity_block_relu4 (A  (None, 14, 14, 1024)         0         ['4e_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4f_identity_block_conv1 (C  (None, 14, 14, 256)          262400    ['4e_identity_block_relu4[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4f_identity_block_bn1 (Bat  (None, 14, 14, 256)          1024      ['4f_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4f_identity_block_relu1 (A  (None, 14, 14, 256)          0         ['4f_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4f_identity_block_conv2 (C  (None, 14, 14, 256)          590080    ['4f_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4f_identity_block_bn2 (Bat  (None, 14, 14, 256)          1024      ['4f_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4f_identity_block_relu2 (A  (None, 14, 14, 256)          0         ['4f_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 4f_identity_block_conv3 (C  (None, 14, 14, 1024)         263168    ['4f_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 4f_identity_block_bn3 (Bat  (None, 14, 14, 1024)         4096      ['4f_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 4f_identity_block_add (Add  (None, 14, 14, 1024)         0         ['4f_identity_block_bn3[0][0]'
 )                                                                  , '4e_identity_block_relu4[0][
                                                                    0]']                          
                                                                                                  
 4f_identity_block_relu4 (A  (None, 14, 14, 1024)         0         ['4f_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 5a_conv_block_conv1 (Conv2  (None, 7, 7, 512)            524800    ['4f_identity_block_relu4[0][0
 D)                                                                 ]']                           
                                                                                                  
 5a_conv_block_bn1 (BatchNo  (None, 7, 7, 512)            2048      ['5a_conv_block_conv1[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 5a_conv_block_relu1 (Activ  (None, 7, 7, 512)            0         ['5a_conv_block_bn1[0][0]']   
 ation)                                                                                           
                                                                                                  
 5a_conv_block_conv2 (Conv2  (None, 7, 7, 512)            2359808   ['5a_conv_block_relu1[0][0]'] 
 D)                                                                                               
                                                                                                  
 5a_conv_block_bn2 (BatchNo  (None, 7, 7, 512)            2048      ['5a_conv_block_conv2[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 5a_conv_block_relu2 (Activ  (None, 7, 7, 512)            0         ['5a_conv_block_bn2[0][0]']   
 ation)                                                                                           
                                                                                                  
 5a_conv_block_conv3 (Conv2  (None, 7, 7, 2048)           1050624   ['5a_conv_block_relu2[0][0]'] 
 D)                                                                                               
                                                                                                  
 5a_conv_block_res_conv (Co  (None, 7, 7, 2048)           2099200   ['4f_identity_block_relu4[0][0
 nv2D)                                                              ]']                           
                                                                                                  
 5a_conv_block_bn3 (BatchNo  (None, 7, 7, 2048)           8192      ['5a_conv_block_conv3[0][0]'] 
 rmalization)                                                                                     
                                                                                                  
 5a_conv_block_res_bn (Batc  (None, 7, 7, 2048)           8192      ['5a_conv_block_res_conv[0][0]
 hNormalization)                                                    ']                            
                                                                                                  
 5a_conv_block_add (Add)     (None, 7, 7, 2048)           0         ['5a_conv_block_bn3[0][0]',   
                                                                     '5a_conv_block_res_bn[0][0]']
                                                                                                  
 5a_conv_block_relu4 (Activ  (None, 7, 7, 2048)           0         ['5a_conv_block_add[0][0]']   
 ation)                                                                                           
                                                                                                  
 5b_identity_block_conv1 (C  (None, 7, 7, 512)            1049088   ['5a_conv_block_relu4[0][0]'] 
 onv2D)                                                                                           
                                                                                                  
 5b_identity_block_bn1 (Bat  (None, 7, 7, 512)            2048      ['5b_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 5b_identity_block_relu1 (A  (None, 7, 7, 512)            0         ['5b_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 5b_identity_block_conv2 (C  (None, 7, 7, 512)            2359808   ['5b_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 5b_identity_block_bn2 (Bat  (None, 7, 7, 512)            2048      ['5b_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 5b_identity_block_relu2 (A  (None, 7, 7, 512)            0         ['5b_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 5b_identity_block_conv3 (C  (None, 7, 7, 2048)           1050624   ['5b_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 5b_identity_block_bn3 (Bat  (None, 7, 7, 2048)           8192      ['5b_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 5b_identity_block_add (Add  (None, 7, 7, 2048)           0         ['5b_identity_block_bn3[0][0]'
 )                                                                  , '5a_conv_block_relu4[0][0]']
                                                                                                  
 5b_identity_block_relu4 (A  (None, 7, 7, 2048)           0         ['5b_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 5c_identity_block_conv1 (C  (None, 7, 7, 512)            1049088   ['5b_identity_block_relu4[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 5c_identity_block_bn1 (Bat  (None, 7, 7, 512)            2048      ['5c_identity_block_conv1[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 5c_identity_block_relu1 (A  (None, 7, 7, 512)            0         ['5c_identity_block_bn1[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 5c_identity_block_conv2 (C  (None, 7, 7, 512)            2359808   ['5c_identity_block_relu1[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 5c_identity_block_bn2 (Bat  (None, 7, 7, 512)            2048      ['5c_identity_block_conv2[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 5c_identity_block_relu2 (A  (None, 7, 7, 512)            0         ['5c_identity_block_bn2[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 5c_identity_block_conv3 (C  (None, 7, 7, 2048)           1050624   ['5c_identity_block_relu2[0][0
 onv2D)                                                             ]']                           
                                                                                                  
 5c_identity_block_bn3 (Bat  (None, 7, 7, 2048)           8192      ['5c_identity_block_conv3[0][0
 chNormalization)                                                   ]']                           
                                                                                                  
 5c_identity_block_add (Add  (None, 7, 7, 2048)           0         ['5c_identity_block_bn3[0][0]'
 )                                                                  , '5b_identity_block_relu4[0][
                                                                    0]']                          
                                                                                                  
 5c_identity_block_relu4 (A  (None, 7, 7, 2048)           0         ['5c_identity_block_add[0][0]'
 ctivation)                                                         ]                             
                                                                                                  
 avg_pool (AveragePooling2D  (None, 1, 1, 2048)           0         ['5c_identity_block_relu4[0][0
 )                                                                  ]']                           
                                                                                                  
 flatten (Flatten)           (None, 2048)                 0         ['avg_pool[0][0]']            
                                                                                                  
 fc1000 (Dense)              (None, 1000)                 2049000   ['flatten[0][0]']             
                                                                                                  
==================================================================================================
Total params: 25636712 (97.80 MB)
Trainable params: 25583592 (97.59 MB)
Non-trainable params: 53120 (207.50 KB)
__________________________________________________________________________________________________

 2. 编译模型

# Compile the model
model.compile(optimizer='adam',
              loss='sparse_categorical_crossentropy',
              metrics=['accuracy'])

3. 训练模型

# Train the model
epochs = 10

history = model.fit(
    train_ds,
    validation_data=val_ds,
    epochs=epochs
)
Epoch 1/10
57/57 [==============================] - 476s 7s/step - loss: 2.3338 - accuracy: 0.4779 - val_loss: 95.4034 - val_accuracy: 0.2301
Epoch 2/10
57/57 [==============================] - 259s 5s/step - loss: 1.0860 - accuracy: 0.6438 - val_loss: 4.2480 - val_accuracy: 0.2920
Epoch 3/10
57/57 [==============================] - 247s 4s/step - loss: 0.7115 - accuracy: 0.7212 - val_loss: 0.9247 - val_accuracy: 0.6637
Epoch 4/10
57/57 [==============================] - 254s 4s/step - loss: 0.7610 - accuracy: 0.7456 - val_loss: 0.7742 - val_accuracy: 0.6903
Epoch 5/10
57/57 [==============================] - 276s 5s/step - loss: 0.5945 - accuracy: 0.7544 - val_loss: 0.6813 - val_accuracy: 0.7434
Epoch 6/10
57/57 [==============================] - 282s 5s/step - loss: 0.6199 - accuracy: 0.8053 - val_loss: 0.9435 - val_accuracy: 0.8053
Epoch 7/10
57/57 [==============================] - 252s 4s/step - loss: 0.5086 - accuracy: 0.8363 - val_loss: 1.8492 - val_accuracy: 0.5752
Epoch 8/10
57/57 [==============================] - 253s 4s/step - loss: 0.3915 - accuracy: 0.8827 - val_loss: 1.2361 - val_accuracy: 0.6018
Epoch 9/10
57/57 [==============================] - 247s 4s/step - loss: 0.5021 - accuracy: 0.8296 - val_loss: 2.4609 - val_accuracy: 0.5929
Epoch 10/10
57/57 [==============================] - 248s 4s/step - loss: 0.5328 - accuracy: 0.8186 - val_loss: 2.3554 - val_accuracy: 0.4779

四、模型评估

1. Loss与Accuracy图

# Evaluate the model
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, label='Training Accuracy')
plt.plot(epochs_range, val_acc, label='Validation Accuracy')
plt.legend(loc='lower right')
plt.title('Training and Validation Accuracy')

plt.subplot(1, 2, 2)

plt.plot(epochs_range, loss, label='Training Loss')
plt.plot(epochs_range, val_loss, label='Validation Loss')
plt.legend(loc='upper right')
plt.title('Training and Validation Loss')
plt.show()

 

 2. 预测

# Predict on new images
plt.figure(figsize=(10, 5))

for images, labels in val_ds.take(1):
    for i in range(8):
        ax = plt.subplot(2, 4, i + 1)

        image = images[i].numpy().astype("uint8")
        plt.imshow(image)

        img_array = tf.expand_dims(images[i], 0)

        predictions = model.predict(img_array)
        plt.title(class_names[np.argmax(predictions)])
        plt.axis("off")
1/1 [==============================] - 2s 2s/step
1/1 [==============================] - 0s 145ms/step
1/1 [==============================] - 0s 157ms/step
1/1 [==============================] - 0s 166ms/step
1/1 [==============================] - 0s 137ms/step
1/1 [==============================] - 0s 126ms/step
1/1 [==============================] - 0s 144ms/step
1/1 [==============================] - 0s 162ms/step

 五、Pytorch版本代码

import os
import pathlib
import numpy as np
import matplotlib.pyplot as plt
from PIL import Image

import torch
from torch import nn
from torchvision import datasets, transforms, models
from torch.utils.data import DataLoader
from torchvision.utils import make_grid

# Set font for Chinese labels (SimHei)
plt.rcParams['font.sans-serif'] = ['SimHei']
plt.rcParams['axes.unicode_minus'] = False

# Paths
data_dir = 'C:/Self_Learning/Deep_Learning/K_Codes/data/8_data/bird_photos/'
data_dir = pathlib.Path(data_dir)

# Transforms
img_height = 224
img_width = 224
batch_size = 8

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

# Load datasets
train_ds = datasets.ImageFolder(data_dir, transform=transform)
class_names = train_ds.classes
num_classes = len(class_names)
print("Classes:", class_names)

# Split into train and val
train_size = int(0.8 * len(train_ds))
val_size = len(train_ds) - train_size
train_dataset, val_dataset = torch.utils.data.random_split(train_ds, [train_size, val_size])

train_loader = DataLoader(train_dataset, batch_size=batch_size, shuffle=True)
val_loader = DataLoader(val_dataset, batch_size=batch_size, shuffle=False)

# Visualise images
def show_batch(images, labels):
    img_grid = make_grid(images, nrow=4)
    npimg = img_grid.numpy()
    plt.figure(figsize=(10, 5))
    plt.imshow(np.transpose(npimg, (1, 2, 0)))
    plt.title(" / ".join([class_names[label] for label in labels]))
    plt.axis("off")
    plt.show()

images, labels = next(iter(train_loader))
show_batch(images, labels)

# Define ResNet50 model
model = models.resnet50(pretrained=False)
model.fc = nn.Linear(model.fc.in_features, num_classes)

# Load pretrained weights if needed (optional)
# model.load_state_dict(torch.load('your_resnet50_weights.pth'))

device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
model = model.to(device)

# Loss & Optimizer
criterion = nn.CrossEntropyLoss()
optimizer = torch.optim.Adam(model.parameters(), lr=0.001)

# Training loop
epochs = 10
train_acc_history = []
val_acc_history = []
train_loss_history = []
val_loss_history = []

for epoch in range(epochs):
    model.train()
    train_loss, train_correct = 0.0, 0

    for inputs, labels in train_loader:
        inputs, labels = inputs.to(device), labels.to(device)

        optimizer.zero_grad()
        outputs = model(inputs)
        loss = criterion(outputs, labels)
        loss.backward()
        optimizer.step()

        train_loss += loss.item() * inputs.size(0)
        train_correct += (outputs.argmax(1) == labels).sum().item()

    train_loss /= len(train_loader.dataset)
    train_acc = train_correct / len(train_loader.dataset)

    # Validation
    model.eval()
    val_loss, val_correct = 0.0, 0
    with torch.no_grad():
        for inputs, labels in val_loader:
            inputs, labels = inputs.to(device), labels.to(device)
            outputs = model(inputs)
            loss = criterion(outputs, labels)

            val_loss += loss.item() * inputs.size(0)
            val_correct += (outputs.argmax(1) == labels).sum().item()

    val_loss /= len(val_loader.dataset)
    val_acc = val_correct / len(val_loader.dataset)

    train_loss_history.append(train_loss)
    val_loss_history.append(val_loss)
    train_acc_history.append(train_acc)
    val_acc_history.append(val_acc)

    print(f"Epoch {epoch+1}/{epochs}: "
          f"Train Loss {train_loss:.4f}, Acc {train_acc:.4f} | "
          f"Val Loss {val_loss:.4f}, Acc {val_acc:.4f}")

# Plot training results
plt.figure(figsize=(12, 4))
plt.subplot(1, 2, 1)
plt.plot(train_acc_history, label='Train Acc')
plt.plot(val_acc_history, label='Val Acc')
plt.legend()
plt.title('Accuracy')

plt.subplot(1, 2, 2)
plt.plot(train_loss_history, label='Train Loss')
plt.plot(val_loss_history, label='Val Loss')
plt.legend()
plt.title('Loss')
plt.show()

# Predict on validation batch
model.eval()
images, labels = next(iter(val_loader))
images = images.to(device)
outputs = model(images)
preds = outputs.argmax(1)

# Show predictions
plt.figure(figsize=(10, 5))
for i in range(8):
    ax = plt.subplot(2, 4, i + 1)
    plt.imshow(images[i].cpu().permute(1, 2, 0).numpy())
    plt.title(class_names[preds[i]])
    plt.axis("off")
plt.show()

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