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# Arguments
directory: Path to the directory to read images from.
Each subdirectory in this directory will be
considered to contain images from one class,
or alternatively you could specify class subdirectories
via the `classes` argument.
image_data_generator: Instance of `ImageDataGenerator`
to use for random transformations and normalization.
target_size: tuple of integers, dimensions to resize input images to.
color_mode: One of `"rgb"`, `"grayscale"`. Color mode to read images.
classes: Optional list of strings, names of sudirectories
containing images from each class (e.g. `["dogs", "cats"]`).
It will be computed automatically if not set.
class_mode: Mode for yielding the targets:
`"binary"`: binary targets (if there are only two classes),
`"categorical"`: categorical targets,
`"sparse"`: integer targets,
`None`: no targets get yielded (only input images are yielded).
batch_size: Integer, size of a batch.
shuffle: Boolean, whether to shuffle the data between epochs.
seed: Random seed for data shuffling.
data_format: String, one of `channels_first`, `channels_last`.
save_to_dir: Optional directory where to save the pictures
being yielded, in a viewable format. This is useful
for visualizing the random transformations being
applied, for debugging purposes.
save_prefix: String prefix to use for saving sample
images (if `save_to_dir` is set).
save_format: Format to use for saving sample images
(if `save_to_dir` is set).
"""
def __init__(self, directory, image_data_generator,
target_size=(256, 256), color_mode='rgb',
classes=None, class_mode='categorical',
batch_size=32, shuffle=True, seed=None,
data_format=None,
save_to_dir=None, save_prefix='', save_format='jpeg',
follow_links=False, file_name_to_y=None, output_function=None):
if data_format is None:
data_format = K.image_data_format()
self.directory = directory
self.image_data_generator = image_data_generator
self.target_size = tuple(target_size)
self.output_function = output_function
self.file_name_to_y = file_name_to_y
if color_mode not in {'rgb', 'grayscale'}:
raise ValueError('Invalid color mode:', color_mode,
'; expected "rgb" or "grayscale".')
self.color_mode = color_mode
self.data_format = data_format
if self.color_mode == 'rgb':
if self.data_format == 'channels_last':
self.image_shape = self.target_size + (3,)
else:
self.image_shape = (3,) + self.target_size
else:
if self.data_format == 'channels_last':
self.image_shape = self.target_size + (1,)
else:
self.image_shape = (1,) + self.target_size
self.classes = classes
if class_mode not in {'categorical', 'binary', 'sparse', 'regression', None}:
raise ValueError('Invalid class_mode:', class_mode,
'; expected one of "categorical", '
'"binary", "sparse", "regression", or None.')
self.class_mode = class_mode
self.save_to_dir = save_to_dir
self.save_prefix = save_prefix
self.save_format = save_format
white_list_formats = {'png', 'jpg', 'jpeg', 'bmp'}
# first, count the number of samples and classes
self.samples = 0
if not classes:
classes = []
for subdir in sorted(os.listdir(directory)):
if os.path.isdir(os.path.join(directory, subdir)):
classes.append(subdir)
self.num_class = len(classes)
self.class_indices = dict(zip(classes, range(len(classes))))
def _recursive_list(subpath):
return sorted(os.walk(subpath, followlinks=follow_links), key=lambda tpl: tpl[0])
for subdir in classes:
subpath = os.path.join(directory, subdir)
for root, _, files in _recursive_list(subpath):
for fname in files:
is_valid = False
for extension in white_list_formats:
if fname.lower().endswith('.' + extension):
is_valid = True
break
if is_valid:
self.samples += 1
print('Found %d images belonging to %d classes.' % (self.samples, self.num_class))