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如何在Keras 2.0中使用InceptionV3瓶颈作为输入

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我想在Keras中使用InceptionV3来利用瓶颈进行转移学习 . 我已经使用了一些关于创建,加载和使用瓶颈的技巧来自https://blog.keras.io/building-powerful-image-classification-models-using-very-little-data.html

我的问题是我不知道如何使用瓶颈(numpy数组)作为具有新顶层的InceptionV3的输入 .

I get the following error:

ValueError:检查输入时出错:期望input_3有形状(None,None,None,3)但是有形状的数组(248,8,8,2048)

248指的是这种情况下的图像总数 .

我知道这行是错的,但我不知道如何纠正它:

model = Model(inputs = base_model.input,outputs = predictions)

将瓶颈输入InceptionV3的正确方法是什么?

Creating the InceptionV3 bottlenecks:

def create_bottlenecks():
datagen = ImageDataGenerator(rescale=1. / 255)

model = InceptionV3(include_top=False, weights='imagenet')

# Generate bottlenecks for all training images
generator = datagen.flow_from_directory(
    train_data_dir,
    target_size=(img_width, img_height),
    batch_size=batch_size,
    class_mode=None,
    shuffle=False)

nb_train_samples = len(generator.filenames)
bottlenecks_train = model.predict_generator(generator, int(math.ceil(nb_train_samples / float(batch_size))), verbose=1)
np.save(open(train_bottlenecks_file, 'w'), bottlenecks_train)

# Generate bottlenecks for all validation images
generator = datagen.flow_from_directory(
    validation_data_dir,
    target_size=(img_width, img_height),
    batch_size=batch_size,
    class_mode=None,
    shuffle=False)

nb_validation_samples = len(generator.filenames)

bottlenecks_validation = model.predict_generator(generator, int(math.ceil(nb_validation_samples / float(batch_size))), verbose=1)
np.save(open(validation_bottlenecks_file, 'w'), bottlenecks_validation)

Loading the bottlenecks:

def load_bottlenecks(src_dir, bottleneck_file):
    datagen = ImageDataGenerator(rescale=1. / 255)
    generator = datagen.flow_from_directory(
        src_dir,
        target_size=(img_width, img_height),
        batch_size=batch_size,
        class_mode='categorical',
        shuffle=False)

    num_classes = len(generator.class_indices)

    # load the bottleneck features saved earlier
    bottleneck_data = np.load(bottleneck_file)

    # get the class lebels for the training data, in the original order
    bottleneck_class_labels = generator.classes

    # convert the training labels to categorical vectors
    bottleneck_class_labels = to_categorical(bottleneck_class_labels, num_classes=num_classes)

    return bottleneck_data, bottleneck_class_labels

Starting training:

def start_training():
global nb_train_samples, nb_validation_samples

create_bottlenecks()

train_data, train_labels = load_bottlenecks(train_data_dir, train_bottlenecks_file)
validation_data, validation_labels = load_bottlenecks(validation_data_dir, validation_bottlenecks_file)

nb_train_samples = len(train_data)
nb_validation_samples = len(validation_data)

base_model = InceptionV3(weights='imagenet', include_top=False)

# add a global spatial average pooling layer
x = base_model.output
x = GlobalAveragePooling2D()(x)

# let's add a fully-connected layer
x = Dense(1024, activation='relu')(x)

# and a logistic layer -- let's say we have 2 classes
predictions = Dense(2, activation='softmax')(x)

# What is the correct input? Obviously not base_model.input.
model = Model(inputs=base_model.input, outputs=predictions)

# first: train only the top layers (which were randomly initialized)
# i.e. freeze all convolutional InceptionV3 layers
for layer in base_model.layers:
    layer.trainable = False

model.compile(optimizer=optimizers.SGD(lr=0.01, momentum=0.9), loss='categorical_crossentropy', metrics=['accuracy'])

# train the model on the new data for a few epochs
history = model.fit(train_data, train_labels,
                    epochs=epochs,
                    batch_size=batch_size,
                    validation_data=(validation_data, validation_labels),
)

任何帮助,将不胜感激!

1 回答

  • 3

    当您尝试使用与模型支持的形状不同的输入数据训练模型时,会发生此错误 .

    您的模型支持 (None, None, None, 3) ,意思是:

    • 任意数量的图像

    • 任何高度

    • 任何宽度

    • 3个 Channels

    因此,您必须确保 train_data (和 validation_data )与此形状匹配 .

    系统告诉 train_data.shape = (248,8,8,2048)

    我看到 train_data 来自 load_botlenecks . 真的应该是从那里来的吗?什么是火车数据应该是什么?一个图像?别的什么?什么是瓶颈?


    您的模型从Inception模型开始,Inception模型采用图像 .

    但是,如果瓶颈已经是Inception模型的结果,并且您想要提供 only 瓶颈,则Inception模型不应该参与任何事情 .

    从...开始:

    inputTensor = Input((8,8,2048)) #Use (None,None,2048) if bottlenecks vary in size    
    x = GlobalAveragePooling2D()(inputTensor)
    
    .....
    

    创建模型:

    model = Model(inputTensor, predictions)
    

    这个想法是:

    • 初始模型:图像 - >初始 - >瓶颈

    • 您的型号:瓶颈 - >型号 - >标签

    只有当您没有预装瓶颈时才需要组合使用这两种模型,但是您有自己的图像需要先预测瓶颈 . (当然你也可以使用不同的模型)

    然后你将只输入图像(瓶颈将由Inception创建并传递给你的模型,内部的一切):

    • 组合模型:图像 - >初始 - >(瓶颈) - >模型 - >标签

    为了那个原因:

    inputImage = Input((None,None,3))
    bottleNecks = base_model(inputImage)
    predictions = model(bottleNecks)
    
    fullModel = Model(inputImage, predictions)
    

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