How to find how many Image Generated By ImageDataGenerator

问题

Hi I want to ask you a question about Keras ImageDataGenerator. Can I determine how many augmented image will create? or how can find training image set size after augmentation.In Keras documentation flow function description is : "Takes numpy data & label arrays, and generates batches of augmented/normalized data. Yields batches indefinitely, in an infinite loop." But how many images generated ?

For example the following code how many image generates ? Infinite ?

from keras.preprocessing.image import ImageDataGenerator, array_to_img, img_to_array, load_img
from matplotlib import pyplot
import numpy as np

datagen = ImageDataGenerator(
        rotation_range=40,
        width_shift_range=0.2,
        height_shift_range=0.2,
        shear_range=0.2,
        zoom_range=0.2,
        horizontal_flip=True,
        fill_mode='nearest')
img=load_img('cat.1.jpg')
x=img_to_array(img)
x = x.reshape((1,) + x.shape) 
print x.shape
h=datagen.flow(x)

回答1:

What you are saying is correct, you can generate an infinite number from one image. This is normal in fact, consider just the number of images you can generate by rotation from the intial, it is infinite, because for each value of rotation angle you can generate a different image. To confirm this I will show this code from keras documentation

for e in range(epochs):
    print('Epoch', e)
    batches = 0
    for x_batch, y_batch in datagen.flow(x_train, y_train, batch_size=32):
        model.fit(x_batch, y_batch)
        batches += 1
        if batches >= len(x_train) / 32:
            # we need to break the loop by hand because
            # the generator loops indefinitely
            break

Note that they are saying that the generator loops indifinitely, which confirms that an infinite amount of images is generated

来源：https://stackoverflow.com/questions/48003732/how-to-find-how-many-image-generated-by-imagedatagenerator