使用 ImageDataGenerator 时的 Keras 分割训练测试集

我有一个目录，其中包含图像的子文件夹（根据标签）。我想在 Keras 中使用 ImageDataGenerator 时将这些数据拆分为训练集和测试集。虽然 keras 中的 model.fit() 有用于指定分割的参数validation_split，但我找不到 model.fit_generator() 的相同参数。怎么做 ？

train_datagen = ImageDataGenerator(rescale=1./255,
    shear_range=0.2,
    zoom_range=0.2,
    horizontal_flip=True)

train_generator = train_datagen.flow_from_directory(
    train_data_dir,
    target_size=(img_width, img_height),
    batch_size=32,
    class_mode='binary')

model.fit_generator(
    train_generator,
    samples_per_epoch=nb_train_samples,
    nb_epoch=nb_epoch,
    validation_data=??,
    nb_val_samples=nb_validation_samples)

我没有单独的验证数据目录，需要将其与训练数据分开

Keras 现在使用 ImageDataGenerator 从单个目录添加了训练/验证拆分：

train_datagen = ImageDataGenerator(rescale=1./255,
    shear_range=0.2,
    zoom_range=0.2,
    horizontal_flip=True,
    validation_split=0.2) # set validation split

train_generator = train_datagen.flow_from_directory(
    train_data_dir,
    target_size=(img_height, img_width),
    batch_size=batch_size,
    class_mode='binary',
    subset='training') # set as training data

validation_generator = train_datagen.flow_from_directory(
    train_data_dir, # same directory as training data
    target_size=(img_height, img_width),
    batch_size=batch_size,
    class_mode='binary',
    subset='validation') # set as validation data

model.fit_generator(
    train_generator,
    steps_per_epoch = train_generator.samples // batch_size,
    validation_data = validation_generator, 
    validation_steps = validation_generator.samples // batch_size,
    epochs = nb_epochs)

https://keras.io/preprocessing/image/ https://keras.io/preprocessing/image/