runtime-error - 用于语义分割的Keras，flow_from_directory()错误

Question

我试图使用我对 Keras 文档中示例代码的修改，该文档展示了在使用图像掩码代替标签的情况下如何设置 image_datagen.flow_from_directory()(对于图像分割，我们在这里为每个像素预测一个类别)。

顺便说一下，我设置了 featurewise_center = True，试图从每个图像的颜色 channel 中减去所有训练图像的每个颜色 channel 的平均值，这样在整个训练集中，每个颜色 channel 的平均值都为 0。我希望这不是实现此目的的方法。

无论如何，这是我产生错误的代码:

image_datagen = ImageDataGenerator(featurewise_center = True)
mask_datagen = ImageDataGenerator()

image_generator = image_datagen.flow_from_directory(
    '/home/icg/Martin/train_data_graz/images_rect_r640x360',
    class_mode = None,
    batch_size = 1,
    seed = 123)

mask_generator = mask_datagen.flow_from_directory(
    '/home/icg/Martin/train_data_graz/labels_rect_r640x360',
    class_mode = None,
    batch_size = 1,
    seed = 123)

# combine generators into one which yields image and masks
train_generator = zip(image_generator, mask_generator)

model.fit_generator(
    train_generator,
    steps_per_epoch = 1000,
    epochs = 100)

这是错误信息:

Found 0 images belonging to 0 classes.
Found 0 images belonging to 0 classes.
Traceback (most recent call last):
  File "FCN_VGG16.py", line 178, in <module>
    train_generator = zip(image_generator, mask_generator)
  File "/home/icg/rafa/local/lib/python2.7/site-packages/keras/preprocessing/image.py", line 1026, in next
    index_array, current_index, current_batch_size = next(self.index_generator)
  File "/home/icg/rafa/local/lib/python2.7/site-packages/keras/preprocessing/image.py", line 720, in _flow_index
    current_index = (self.batch_index * batch_size) % n
ZeroDivisionError: integer division or modulo by zero

由于某种原因 n = 0。知道为什么会发生这种情况吗？

Answer 1

您需要将每个类的图像放入 子文件夹 到您的 flow_from_directory() 函数的目录中。

在你的情况下:

/home/icg/Martin/train_data_graz/images_rect_r640x360/images_class01
/home/icg/Martin/train_data_graz/images_rect_r640x360/images_class02
…

编辑:

由于您已将 class_mode 设置为 None 并进行语义分割(请参阅评论和帖子):

/home/icg/Martin/train_data_graz/images_rect_r640x360/all_images