【深度学习】Keras自建神经网络模型实现133种狗的种类识别（记录笔记）

àì夳堔傛蜴生んèń 2022-11-01 13:48 211阅读 0赞

## 〇、内容说明 ##

主体部分资料来源于：  
[1、【深度学习图像识别课程】毕业项目：狗狗种类识别（2）代码实现][1_2]

[2、项目：实现一个狗品种识别算法App][2_App]

[3、Kaggle相关比赛：Dog Breed Identification][3_Kaggle_Dog Breed Identification]

## 一、加载数据 ##

from sklearn.datasets import load_files       
    from keras.utils import np_utils
    import numpy as np
    from glob import glob
    import time
    t0=time.time()
    print('显示此刻的时间:',time.strftime('%Y-%m-%d %H:%M:%S',time.localtime(time.time())))
    
    # 定义函数来加载train，test和validation数据集
    def load_dataset(path):
        data = load_files(path)
        dog_files = np.array(data['filenames'])
        dog_targets = np_utils.to_categorical(np.array(data['target']), 133)
        return dog_files, dog_targets
    
    # 加载train，test和validation数据集
    train_files, train_targets = load_dataset('E:/dog/dogImages/train')
    valid_files, valid_targets = load_dataset('E:/dog/dogImages/valid')
    test_files, test_targets = load_dataset('E:/dog/dogImages/test')
    
    # 加载狗品种列表
    dog_names = [item[20:-1] for item in sorted(glob("E:/dog/dogImages/train/*/"))]
    
    # 打印数据统计描述
    print('There are %d total dog categories.' % len(dog_names))
    print('There are %s total dog images.\n' % len(np.hstack([train_files, valid_files, test_files])))
    print('There are %d training dog images.' % len(train_files))
    print('There are %d validation dog images.' % len(valid_files))
    print('There are %d test dog images.'% len(test_files))
    
    t1=time.time()
    print('显示结束的时间:',time.strftime('%Y-%m-%d %H:%M:%S',time.localtime(time.time())))
    print("用时：%.2fs"%(t1-t0))

![在这里插入图片描述][20210224161450722.png]

## 二、处理数据 ##

调整载入的图片数据格式，使其符合keras模型的输入的要求

from keras.preprocessing import image                  
    from tqdm import tqdm
    
    def path_to_tensor(img_path):
        # 用PIL加载RGB图像为PIL.Image.Image类型
        img = image.load_img(img_path, target_size=(224, 224))
        # 将PIL.Image.Image类型转化为格式为(224, 224, 3)的3维张量
        x = image.img_to_array(img)
        # 将3维张量转化为格式为(1, 224, 224, 3)的4维张量并返回
        return np.expand_dims(x, axis=0)
    
    def paths_to_tensor(img_paths):
        list_of_tensors = [path_to_tensor(img_path) for img_path in tqdm(img_paths)]
        return np.vstack(list_of_tensors)
    
    from PIL import ImageFile                            
    ImageFile.LOAD_TRUNCATED_IMAGES = True                 
    
    # Keras中的数据预处理过程
    train_tensors = paths_to_tensor(train_files).astype('float32')/255
    valid_tensors = paths_to_tensor(valid_files).astype('float32')/255
    test_tensors = paths_to_tensor(test_files).astype('float32')/255

![在这里插入图片描述][2021022416153931.png]

插个补充：[Application应用-Keras中文文档（Resnet50）][Application_-Keras_Resnet50]  
这里处理数据的思路是类似的

from keras.applications.resnet50 import ResNet50
    from keras.preprocessing import image
    from keras.applications.resnet50 import preprocess_input, decode_predictions
    import numpy as np
    
    model = ResNet50(weights='imagenet',classes=12)
    
    img_path = 'rubber.jpg'
    img = image.load_img(img_path, target_size=(224, 224))
    x = image.img_to_array(img)
    a = np.expand_dims(x, axis=0)
    b = preprocess_input(a)
    
    preds = model.predict(b)
    # 将结果解码为元组列表 (class, description, probability)
    # (一个列表代表批次中的一个样本）
    print('Predicted:', decode_predictions(preds, top=3)[0])
    # Predicted: [(u'n02504013', u'Indian_elephant', 0.82658225), (u'n01871265'

## 三、Keras自建模型 ##

from keras.layers import Conv2D, MaxPooling2D, GlobalAveragePooling2D
    from keras.layers import Dropout, Flatten, Dense
    from keras.models import Sequential
    
    model = Sequential()
    
    ### TODO: 定义你的网络架构
    model.add(Conv2D(filters=16, kernel_size=2, padding='valid', activation='relu', input_shape=(224,224,3)))
    model.add(MaxPooling2D(pool_size=2))
    model.add(Conv2D(filters=32, kernel_size=2, padding='valid', activation='relu'))
    model.add(MaxPooling2D(pool_size=2))
    model.add(Conv2D(filters=64, kernel_size=2, padding='valid', activation='relu'))
    model.add(MaxPooling2D(pool_size=2))
    model.add(GlobalAveragePooling2D(input_shape=(27,27,64)))
    model.add(Dense(133, activation='softmax'))
    
                     
    model.summary()

这个模型的乍一看感觉很有Let-Net5的感觉，但确实也不是。

神经网络模型千变万化，稍微变化结果便会产生差异，玄之又玄。

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxODU2NzMz_size_16_color_FFFFFF_t_70]  
补充一个经典Let-Net5模型：

from keras.models import Sequential, Model
    from keras.layers import Conv2D, MaxPooling2D
    from keras.layers import Activation, Flatten
    from keras.layers import Dense,Input, Embedding, LSTM, Dropout
    
    model = Sequential()
    model.add(Conv2D(6, (5, 5), input_shape=(32, 32,3)))
    model.add(Activation('relu'))
    model.add(MaxPooling2D(pool_size=(2, 2)))
    model.add(Conv2D(16, (5, 5), activation='relu'))
    model.add(MaxPooling2D(pool_size=(2, 2)))
    model.add(Flatten())
    model.add(Dense(120, activation='relu'))
    model.add(Dense(84, activation='relu'))
    model.add(Dense(10, activation='softmax'))
    
    model.summary()

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxODU2NzMz_size_16_color_FFFFFF_t_70 1]

## 四、编译训练模型 ##

## 编译模型
    model.compile(optimizer='rmsprop', loss='categorical_crossentropy', metrics=['accuracy'])
    
    from keras.callbacks import ModelCheckpoint  
    checkpointer = ModelCheckpoint(filepath='weights.best.from_scratch.hdf5', 
                                   verbose=1, save_best_only=True)
    
    model.fit(train_tensors, train_targets, 
              validation_data=(valid_tensors, valid_targets),
              epochs=20, batch_size=25, callbacks=[checkpointer], verbose=1)

过拟合：训练精度越来越高，验证数据精度不变  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxODU2NzMz_size_16_color_FFFFFF_t_70 2]

## 五、加载并测试 ##

## 加载具有最好验证loss的模型
    model.load_weights('saved_models/weights.best.from_scratch.hdf5')
    
    # 获取测试数据集中每一个图像所预测的狗品种的index
    dog_breed_predictions = [np.argmax(model.predict(np.expand_dims(tensor, axis=0))) for tensor in test_tensors]
    
    # 报告测试准确率
    test_accuracy = 100*np.sum(np.array(dog_breed_predictions)==np.argmax(test_targets, axis=1))/len(dog_breed_predictions)
    print('Test accuracy: %.4f%%' % test_accuracy)

Test accuracy: 7.2967%

模型比较简陋，隐层也不多，20epoch，CPU训练时间将近一小时，结果还算可以！

[1_2]: https://blog.csdn.net/weixin_41770169/article/details/80481858
[2_App]: https://github.com/udacity/cn-deep-learning/blob/master/dog-project/dog_app.ipynb
[3_Kaggle_Dog Breed Identification]: https://www.kaggle.com/c/dog-breed-identification/notebooks
[20210224161450722.png]: /images/20221024/61c5c72a537847ce9f0515fe7af5d34a.png
[2021022416153931.png]: /images/20221024/34bc4ea5d6bc44f2a04ad69be5c3dc05.png
[Application_-Keras_Resnet50]: https://keras-cn.readthedocs.io/en/latest/other/application/#resnet50
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxODU2NzMz_size_16_color_FFFFFF_t_70]: /images/20221024/1d3ca58272804c24aa4b0c500db36d2a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxODU2NzMz_size_16_color_FFFFFF_t_70 1]: /images/20221024/bed4d7d77ee04d2c956ceb2530da2da6.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxODU2NzMz_size_16_color_FFFFFF_t_70 2]: /images/20221024/c76ea6391dfd413f91f66362e6538d93.png