"""Utilities for real-time data augmentation on image data.
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import numpy as np
import re
from scipy import linalg
import scipy.ndimage as ndi
from six.moves import range
import os
import threading
import warnings
import multiprocessing.pool
import cv2
from functools import partial
from skimage import data, img_as_float
from skimage import exposure
from . import get_keras_submodule
backend = get_keras_submodule('backend')
keras_utils = get_keras_submodule('utils')
try:
from PIL import ImageEnhance
from PIL import Image as pil_image
except ImportError:
pil_image = None
if pil_image is not None:
_PIL_INTERPOLATION_METHODS = {
'nearest': pil_image.NEAREST,
'bilinear': pil_image.BILINEAR,
'bicubic': pil_image.BICUBIC,
'antialias' : pil_image.ANTIALIAS,
}
# These methods were only introduced in version 3.4.0 (2016).
if hasattr(pil_image, 'HAMMING'):
_PIL_INTERPOLATION_METHODS['hamming'] = pil_image.HAMMING
if hasattr(pil_image, 'BOX'):
_PIL_INTERPOLATION_METHODS['box'] = pil_image.BOX
# This method is new in version 1.1.3 (2013).
if hasattr(pil_image, 'LANCZOS'):
_PIL_INTERPOLATION_METHODS['lanczos'] = pil_image.LANCZOS
def random_rotation(x, rg, row_axis=1, col_axis=2, channel_axis=0,
fill_mode='nearest', cval=0.):
"""Performs a random rotation of a Numpy image tensor.
# Arguments
x: Input tensor. Must be 3D.
rg: Rotation range, in degrees.
row_axis: Index of axis for rows in the input tensor.
col_axis: Index of axis for columns in the input tensor.
channel_axis: Index of axis for channels in the input tensor.
fill_mode: Points outside the boundaries of the input
are filled according to the given mode
(one of `{'constant', 'nearest', 'reflect', 'wrap'}`).
cval: Value used for points outside the boundaries
of the input if `mode='constant'`.
# Returns
Rotated Numpy image tensor.
"""
theta = np.random.uniform(-rg, rg)
x = apply_affine_transform(x, theta=theta, channel_axis=channel_axis,
fill_mode=fill_mode, cval=cval)
return x
def random_shift(x, wrg, hrg, row_axis=1, col_axis=2, channel_axis=0,
fill_mode='nearest', cval=0.):
"""Performs a random spatial shift of a Numpy image tensor.
# Arguments
x: Input tensor. Must be 3D.
wrg: Width shift range, as a float fraction of the width.
hrg: Height shift range, as a float fraction of the height.
row_axis: Index of axis for rows in the input tensor.
col_axis: Index of axis for columns in the input tensor.
channel_axis: Index of axis for channels in the input tensor.
fill_mode: Points outside the boundaries of the input
are filled according to the given mode
(one of `{'constant', 'nearest', 'reflect', 'wrap'}`).
cval: Value used for points outside the boundaries
of the input if `mode='constant'`.
# Returns
Shifted Numpy image tensor.
"""
h, w = x.shape[row_axis], x.shape[col_axis]
tx = np.random.uniform(-hrg, hrg) * h
ty = np.random.uniform(-wrg, wrg) * w
x = apply_affine_transform(x, tx=tx, ty=ty, channel_axis=channel_axis,
fill_mode=fill_mode, cval=cval)
return x
def random_shear(x, intensity, row_axis=1, col_axis=2, channel_axis=0,
fill_mode='nearest', cval=0.):
"""Performs a random spatial shear of a Numpy image tensor.
# Arguments
x: Input tensor. Must be 3D.
intensity: Transformation intensity in degrees.
row_axis: Index of axis for rows in the input tensor.
col_axis: Index of axis for columns in the input tensor.
channel_axis: Index of axis for channels in the input tensor.
fill_mode: Points outside the boundaries of the input
are filled according to the given mode
(one of `{'constant', 'nearest', 'reflect', 'wrap'}`).
cval: Value used for points outside the boundaries
of the input if `mode='constant'`.
# Returns
Sheared Numpy image tensor.
"""
shear = np.random.uniform(-intensity, intensity)
x = apply_affine_transform(x, shear=shear, channel_axis=channel_axis,
fill_mode=fill_mode, cval=cval)
return x
def random_zoom(x, zoom_range, row_axis=1, col_axis=2, channel_axis=0,
fill_mode='nearest', cval=0.):
"""Performs a random spatial zoom of a Numpy image tensor.
# Arguments
x: Input tensor. Must be 3D.
zoom_range: Tuple of floats; zoom range for width and height.
row_axis: Index of axis for rows in the input tensor.
col_axis: Index of axis for columns in the input tensor.
channel_axis: Index of axis for channels in the input tensor.
fill_mode: Points outside the boundaries of the input
are filled according to the given mode
(one of `{'constant', 'nearest', 'reflect', 'wrap'}`).
cval: Value used for points outside the boundaries
of the input if `mode='constant'`.
# Returns
Zoomed Numpy image tensor.
# Raises
ValueError: if `zoom_range` isn't a tuple.
"""
if len(zoom_range) != 2:
raise ValueError('`zoom_range` should be a tuple or list of two'
' floats. Received: ', zoom_range)
if zoom_range[0] == 1 and zoom_range[1] == 1:
zx, zy = 1, 1
else:
zx, zy = np.random.uniform(zoom_range[0], zoom_range[1], 2)
x = apply_affine_transform(x, zx=zx, zy=zy, channel_axis=channel_axis,
fill_mode=fill_mode, cval=cval)
return x
def apply_channel_shift(x, intensity, channel_axis=0):
"""Performs a channel shift.
# Arguments
x: Input tensor. Must be 3D.
intensity: Transformation intensity.
channel_axis: Index of axis for channels in the input tensor.
# Returns
Numpy image tensor.
"""
x = np.rollaxis(x, channel_axis, 0)
min_x, max_x = np.min(x), np.max(x)
channel_images = [
np.clip(x_channel + intensity,
min_x,
max_x)
for x_channel in x]
x = np.stack(channel_images, axis=0)
x = np.rollaxis(x, 0, channel_axis + 1)
return x
def random_channel_shift(x, intensity_range, channel_axis=0):
"""Performs a random channel shift.
# Arguments
x: Input tensor. Must be 3D.
intensity_range: Transformation intensity.
channel_axis: Index of axis for channels in the input tensor.
# Returns
Numpy image tensor.
"""
intensity = np.random.uniform(-intensity_range, intensity_range)
return apply_channel_shift(x, intensity, channel_axis=channel_axis)
def apply_brightness_shift(x, brightness):
"""Performs a brightness shift.
# Arguments
x: Input tensor. Must be 3D.
brightness: Float. The new brightness value.
channel_axis: Index of axis for channels in the input tensor.
# Returns
Numpy image tensor.
# Raises
ValueError if `brightness_range` isn't a tuple.
"""
x = array_to_img(x)
x = imgenhancer_Brightness = ImageEnhance.Brightness(x)
x = imgenhancer_Brightness.enhance(brightness)
x = img_to_array(x)
return x
def random_brightness(x, brightness_range):
"""Performs a random brightness shift.
# Arguments
x: Input tensor. Must be 3D.
brightness_range: Tuple of floats; brightness range.
channel_axis: Index of axis for channels in the input tensor.
# Returns
Numpy image tensor.
# Raises
ValueError if `brightness_range` isn't a tuple.
"""
if len(brightness_range) != 2:
raise ValueError(
'`brightness_range should be tuple or list of two floats. '
'Received: %s' % brightness_range)
u = np.random.uniform(brightness_range[0], brightness_range[1])
return apply_brightness_shift(x, u)
def transform_matrix_offset_center(matrix, x, y):
o_x = float(x) / 2 + 0.5
o_y = float(y) / 2 + 0.5
offset_matrix = np.array([[1, 0, o_x], [0, 1, o_y], [0, 0, 1]])
reset_matrix = np.array([[1, 0, -o_x], [0, 1, -o_y], [0, 0, 1]])
transform_matrix = np.dot(np.dot(offset_matrix, matrix), reset_matrix)
return transform_matrix
def apply_affine_transform(x, theta=0, tx=0, ty=0, shear=0, zx=1, zy=1,
row_axis=0, col_axis=1, channel_axis=2,
fill_mode='nearest', cval=0.):
"""Applies an affine transformation specified by the parameters given.
# Arguments
x: 2D numpy array, single image.
theta: Rotation angle in degrees.
tx: Width shift.
ty: Heigh shift.
shear: Shear angle in degrees.
zx: Zoom in x direction.
zy: Zoom in y direction
row_axis: Index of axis for rows in the input image.
col_axis: Index of axis for columns in the input image.
channel_axis: Index of axis for channels in the input image.
fill_mode: Points outside the boundaries of the input
are filled according to the given mode
(one of `{'constant', 'nearest', 'reflect', 'wrap'}`).
cval: Value used for points outside the boundaries
of the input if `mode='constant'`.
# Returns
The transformed version of the input.
"""
transform_matrix = None
if theta != 0:
theta = np.deg2rad(theta)
rotation_matrix = np.array([[np.cos(theta), -np.sin(theta), 0],
[np.sin(theta), np.cos(theta), 0],
[0, 0, 1]])
transform_matrix = rotation_matrix
if tx != 0 or ty != 0:
shift_matrix = np.array([[1, 0, tx],
[0, 1, ty],
[0, 0, 1]])
if transform_matrix is None:
transform_matrix = shift_matrix
else:
transform_matrix = np.dot(transform_matrix, shift_matrix)
if shear != 0:
shear = np.deg2rad(shear)
shear_matrix = np.array([[1, -np.sin(shear), 0],
[0, np.cos(shear), 0],
[0, 0, 1]])
if transform_matrix is None:
transform_matrix = shear_matrix
else:
transform_matrix = np.dot(transform_matrix, shear_matrix)
if zx != 1 or zy != 1:
zoom_matrix = np.array([[zx, 0, 0],
[0, zy, 0],
[0, 0, 1]])
if transform_matrix is None:
transform_matrix = zoom_matrix
else:
transform_matrix = np.dot(transform_matrix, zoom_matrix)
if transform_matrix is not None:
h, w = x.shape[row_axis], x.shape[col_axis]
transform_matrix = transform_matrix_offset_center(
transform_matrix, h, w)
x = np.rollaxis(x, channel_axis, 0)
final_affine_matrix = transform_matrix[:2, :2]
final_offset = transform_matrix[:2, 2]
channel_images = [ndi.interpolation.affine_transform(
x_channel,
final_affine_matrix,
final_offset,
order=1,
mode=fill_mode,
cval=cval) for x_channel in x]
x = np.stack(channel_images, axis=0)
x = np.rollaxis(x, 0, channel_axis + 1)
return x
def rgb2gray(rgb):
r,g,b = rgb[:,:,0], rgb[:,:,1], rgb[:,:,2]
gray = 0.2989* r + 0.5870*g + 0.1140*b
return gray
def flip_axis(x, axis):
x = np.asarray(x).swapaxes(axis, 0)
x = x[::-1, ...]
x = x.swapaxes(0, axis)
return x
def array_to_img(x, data_format=None, scale=True):
"""Converts a 3D Numpy array to a PIL Image instance.
# Arguments
x: Input Numpy array.
data_format: Image data format.
either "channels_first" or "channels_last".
scale: Whether to rescale image values
to be within `[0, 255]`.
# Returns
A PIL Image instance.
# Raises
ImportError: if PIL is not available.
ValueError: if invalid `x` or `data_format` is passed.
"""
if pil_image is None:
raise ImportError('Could not import PIL.Image. '
'The use of `array_to_img` requires PIL.')
x = np.asarray(x, dtype=backend.floatx())
if x.ndim != 3:
raise ValueError('Expected image array to have rank 3 (single image). '
'Got array with shape:', x.shape)
if data_format is None:
data_format = backend.image_data_format()
if data_format not in {'channels_first', 'channels_last'}:
raise ValueError('Invalid data_format:', data_format)
# Original Numpy array x has format (height, width, channel)
# or (channel, height, width)
# but target PIL image has format (width, height, channel)
if data_format == 'channels_first':
x = x.transpose(1, 2, 0)
if scale:
x = x + max(-np.min(x), 0)
x_max = np.max(x)
if x_max != 0:
x /= x_max
x *= 255
if x.shape[2] == 3:
# RGB
return pil_image.fromarray(x.astype('uint8'), 'RGB')
elif x.shape[2] == 1:
# grayscale
return pil_image.fromarray(x[:, :, 0].astype('uint8'), 'L')
else:
raise ValueError('Unsupported channel number: ', x.shape[2])
def img_to_array(img, data_format=None):
"""Converts a PIL Image instance to a Numpy array.
# Arguments
img: PIL Image instance.
data_format: Image data format,
either "channels_first" or "channels_last".
# Returns
A 3D Numpy array.
# Raises
ValueError: if invalid `img` or `data_format` is passed.
"""
if data_format is None:
data_format = backend.image_data_format()
if data_format not in {'channels_first', 'channels_last'}:
raise ValueError('Unknown data_format: ', data_format)
# Numpy array x has format (height, width, channel)
# or (channel, height, width)
# but original PIL image has format (width, height, channel)
x = np.asarray(img, dtype=backend.floatx())
if len(x.shape) == 3:
if data_format == 'channels_first':
x = x.transpose(2, 0, 1)
elif len(x.shape) == 2:
if data_format == 'channels_first':
x = x.reshape((1, x.shape[0], x.shape[1]))
else:
x = x.reshape((x.shape[0], x.shape[1], 1))
else:
raise ValueError('Unsupported image shape: ', x.shape)
return x
def save_img(path,
x,
data_format=None,
file_format=None,
scale=True, **kwargs):
"""Saves an image stored as a Numpy array to a path or file object.
# Arguments
path: Path or file object.
x: Numpy array.
data_format: Image data format,
either "channels_first" or "channels_last".
file_format: Optional file format override. If omitted, the
format to use is determined from the filename extension.
If a file object was used instead of a filename, this
parameter should always be used.
scale: Whether to rescale image values to be within `[0, 255]`.
**kwargs: Additional keyword arguments passed to `PIL.Image.save()`.
"""
img = array_to_img(x, data_format=data_format, scale=scale)
img.save(path, format=file_format, **kwargs)
def load_img(path, grayscale=False, target_size=None,
interpolation='nearest'): #nearest
"""Loads an image into PIL format.
# Arguments
path: Path to image file.
grayscale: Boolean, whether to load the image as grayscale.
target_size: Either `None` (default to original size)
or tuple of ints `(img_height, img_width)`.
interpolation: Interpolation method used to resample the image if the
target size is different from that of the loaded image.
Supported methods are "nearest", "bilinear", and "bicubic".
If PIL version 1.1.3 or newer is installed, "lanczos" is also
supported. If PIL version 3.4.0 or newer is installed, "box" and
"hamming" are also supported. By default, "nearest" is used.
# Returns
A PIL Image instance.
# Raises
ImportError: if PIL is not available.
ValueError: if interpolation method is not supported.
"""
if pil_image is None:
raise ImportError('Could not import PIL.Image. '
'The use of `array_to_img` requires PIL.')
img = pil_image.open(path)
if grayscale:
if img.mode != 'L':
img = img.convert('L')
else:
if img.mode != 'RGB':
img = img.convert('RGB')
if target_size is not None:
width_height_tuple = (target_size[1], target_size[0])
if img.size != width_height_tuple:
if interpolation not in _PIL_INTERPOLATION_METHODS:
raise ValueError(
'Invalid interpolation method {} specified. Supported '
'methods are {}'.format(
interpolation,
", ".join(_PIL_INTERPOLATION_METHODS.keys())))
resample = _PIL_INTERPOLATION_METHODS[interpolation]
img = img.resize(width_height_tuple, resample)
return img
def list_pictures(directory, ext='jpg|jpeg|bmp|png|ppm'):
return [os.path.join(root, f)
for root, _, files in os.walk(directory) for f in files
if re.match(r'([\w]+\.(?:' + ext + '))', f.lower())]
class ImageDataGenerator(object):
"""Generate batches of tensor image data with real-time data augmentation.
The data will be looped over (in batches).
# Arguments
featurewise_center: Boolean.
Set input mean to 0 over the dataset, feature-wise.
samplewise_center: Boolean. Set each sample mean to 0.
featurewise_std_normalization: Boolean.
Divide inputs by std of the dataset, feature-wise.
samplewise_std_normalization: Boolean. Divide each input by its std.
zca_epsilon: epsilon for ZCA whitening. Default is 1e-6.
zca_whitening: Boolean. Apply ZCA whitening.
rotation_range: Int. Degree range for random rotations.
width_shift_range: Float, 1-D array-like or int
- float: fraction of total width, if < 1, or pixels if >= 1.
- 1-D array-like: random elements from the array.
- int: integer number of pixels from interval
`(-width_shift_range, +width_shift_range)`
- With `width_shift_range=2` possible values
are integers `[-1, 0, +1]`,
same as with `width_shift_range=[-1, 0, +1]`,
while with `width_shift_range=1.0` possible values are floats
in the interval [-1.0, +1.0).
height_shift_range: Float, 1-D array-like or int
- float: fraction of total height, if < 1, or pixels if >= 1.
- 1-D array-like: random elements from the array.
- int: integer number of pixels from interval
`(-height_shift_range, +height_shift_range)`
- With `height_shift_range=2` possible values
are integers `[-1, 0, +1]`,
same as with `height_shift_range=[-1, 0, +1]`,
while with `height_shift_range=1.0` possible values are floats
in the interval [-1.0, +1.0).
shear_range: Float. Shear Intensity
(Shear angle in counter-clockwise direction in degrees)
zoom_range: Float or [lower, upper]. Range for random zoom.
If a float, `[lower, upper] = [1-zoom_range, 1+zoom_range]`.
channel_shift_range: Float. Range for random channel shifts.
fill_mode: One of {"constant", "nearest", "reflect" or "wrap"}.
Default is 'nearest'.
Points outside the boundaries of the input are filled
according to the given mode:
- 'constant': kkkkkkkk|abcd|kkkkkkkk (cval=k)
- 'nearest': aaaaaaaa|abcd|dddddddd
- 'reflect': abcddcba|abcd|dcbaabcd
- 'wrap': abcdabcd|abcd|abcdabcd
cval: Float or Int.
Value used for points outside the boundaries
when `fill_mode = "constant"`.
horizontal_flip: Boolean. Randomly flip inputs horizontally.
vertical_flip: Boolean. Randomly flip inputs vertically.
rescale: rescaling factor. Defaults to None.
If None or 0, no rescaling is applied,
otherwise we multiply the data by the value provided
(before applying any other transformation).
preprocessing_function: function that will be implied on each input.
The function will run after the image is resized and augmented.
The function should take one argument:
one image (Numpy tensor with rank 3),
and should output a Numpy tensor with the same shape.
data_format: Image data format,
either "channels_first" or "channels_last".
"channels_last" mode means that the images should have shape
`(samples, height, width, channels)`,
"channels_first" mode means that the images should have shape
`(samples, channels, height, width)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
validation_split: Float. Fraction of images reserved for validation
(strictly between 0 and 1).
# Examples
Example of using `.flow(x, y)`:
```python
(x_train, y_train), (x_test, y_test) = cifar10.load_data()
y_train = np_utils.to_categorical(y_train, num_classes)
y_test = np_utils.to_categorical(y_test, num_classes)
datagen = ImageDataGenerator(
featurewise_center=True,
featurewise_std_normalization=True,
rotation_range=20,
width_shift_range=0.2,
height_shift_range=0.2,
horizontal_flip=True)
# compute quantities required for featurewise normalization
# (std, mean, and principal components if ZCA whitening is applied)
datagen.fit(x_train)
# fits the model on batches with real-time data augmentation:
model.fit_generator(datagen.flow(x_train, y_train, batch_size=32),
steps_per_epoch=len(x_train) / 32, epochs=epochs)
# here's a more "manual" example
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
```
Example of using `.flow_from_directory(directory)`:
```python
train_datagen = ImageDataGenerator(
rescale=1./255,
shear_range=0.2,
zoom_range=0.2,
horizontal_flip=True)
test_datagen = ImageDataGenerator(rescale=1./255)
train_generator = train_datagen.flow_from_directory(
'data/train',
target_size=(150, 150),
batch_size=32,
class_mode='binary')
validation_generator = test_datagen.flow_from_directory(
'data/validation',
target_size=(150, 150),
batch_size=32,
class_mode='binary')
model.fit_generator(
train_generator,
steps_per_epoch=2000,
epochs=50,
validation_data=validation_generator,
validation_steps=800)
```
Example of transforming images and masks together.
```python
# we create two instances with the same arguments
data_gen_args = dict(featurewise_center=True,
featurewise_std_normalization=True,
rotation_range=90.,
width_shift_range=0.1,
height_shift_range=0.1,
zoom_range=0.2)
image_datagen = ImageDataGenerator(**data_gen_args)
mask_datagen = ImageDataGenerator(**data_gen_args)
# Provide the same seed and keyword arguments to the fit and flow methods
seed = 1
image_datagen.fit(images, augment=True, seed=seed)
mask_datagen.fit(masks, augment=True, seed=seed)
image_generator = image_datagen.flow_from_directory(
'data/images',
class_mode=None,
seed=seed)
mask_generator = mask_datagen.flow_from_directory(
'data/masks',
class_mode=None,
seed=seed)
# combine generators into one which yields image and masks
train_generator = zip(image_generator, mask_generator)
model.fit_generator(
train_generator,
steps_per_epoch=2000,
epochs=50)
```
"""
def __init__(self,
contrast_stretching=False,
histogram_equalization=False,
adaptive_equalization=False,
featurewise_center=False,
samplewise_center=False,
featurewise_std_normalization=False,
samplewise_std_normalization=False,
zca_whitening=False,
zca_epsilon=1e-6,
rotation_range=0.,
width_shift_range=0.,
height_shift_range=0.,
brightness_range=None,
shear_range=0.,
zoom_range=0.,
channel_shift_range=0.,
fill_mode='nearest',
cval=0.,
horizontal_flip=False,
vertical_flip=False,
rescale=None,
preprocessing_function=None,
data_format=None,
validation_split=0.0):
if data_format is None:
data_format = backend.image_data_format()
self.contrast_stretching = contrast_stretching
self.histogram_equalization = histogram_equalization
self.adaptive_equalization = adaptive_equalization
self.featurewise_center = featurewise_center
self.samplewise_center = samplewise_center
self.featurewise_std_normalization = featurewise_std_normalization
self.samplewise_std_normalization = samplewise_std_normalization
self.zca_whitening = zca_whitening
self.zca_epsilon = zca_epsilon
self.rotation_range = rotation_range
self.width_shift_range = width_shift_range
self.height_shift_range = height_shift_range
self.brightness_range = brightness_range
self.shear_range = shear_range
self.zoom_range = zoom_range
self.channel_shift_range = channel_shift_range
self.fill_mode = fill_mode
self.cval = cval
self.horizontal_flip = horizontal_flip
self.vertical_flip = vertical_flip
self.rescale = rescale
self.preprocessing_function = preprocessing_function
if data_format not in {'channels_last', 'channels_first'}:
raise ValueError(
'`data_format` should be `"channels_last"` '
'(channel after row and column) or '
'`"channels_first"` (channel before row and column). '
'Received: %s' % data_format)
self.data_format = data_format
if data_format == 'channels_first':
self.channel_axis = 1
self.row_axis = 2
self.col_axis = 3
if data_format == 'channels_last':
self.channel_axis = 3
self.row_axis = 1
self.col_axis = 2
if validation_split and not 0 < validation_split < 1:
raise ValueError(
'`validation_split` must be strictly between 0 and 1. '
' Received: %s' % validation_split)
self._validation_split = validation_split
self.mean = None
self.std = None
self.principal_components = None
if np.isscalar(zoom_range):
self.zoom_range = [1 - zoom_range, 1 + zoom_range]
elif len(zoom_range) == 2:
self.zoom_range = [zoom_range[0], zoom_range[1]]
else:
raise ValueError('`zoom_range` should be a float or '
'a tuple or list of two floats. '
'Received: %s' % zoom_range)
if zca_whitening:
if not featurewise_center:
self.featurewise_center = True
warnings.warn('This ImageDataGenerator specifies '
'`zca_whitening`, which overrides '
'setting of `featurewise_center`.')
if featurewise_std_normalization:
self.featurewise_std_normalization = False
warnings.warn('This ImageDataGenerator specifies '
'`zca_whitening` '
'which overrides setting of'
'`featurewise_std_normalization`.')
if featurewise_std_normalization:
if not featurewise_center:
self.featurewise_center = True
warnings.warn('This ImageDataGenerator specifies '
'`featurewise_std_normalization`, '
'which overrides setting of '
'`featurewise_center`.')
if samplewise_std_normalization:
if not samplewise_center:
self.samplewise_center = True
warnings.warn('This ImageDataGenerator specifies '
'`samplewise_std_normalization`, '
'which overrides setting of '
'`samplewise_center`.')
def flow(self, x,
y=None, batch_size=32, shuffle=True,
sample_weight=None, seed=None,
save_to_dir=None, save_prefix='', save_format='png', subset=None):
"""Takes data & label arrays, generates batches of augmented data.
# Arguments
x: Input data. Numpy array of rank 4 or a tuple.
If tuple, the first element
should contain the images and the second element
another numpy array or a list of numpy arrays
that gets passed to the output
without any modifications.
Can be used to feed the model miscellaneous data
along with the images.
In case of grayscale data, the channels axis of the image array
should have value 1, and in case
of RGB data, it should have value 3.
y: Labels.
batch_size: Int (default: 32).
shuffle: Boolean (default: True).
sample_weight: Sample weights.
seed: Int (default: None).
save_to_dir: None or str (default: None).
This allows you to optionally specify a directory
to which to save the augmented pictures being generated
(useful for visualizing what you are doing).
save_prefix: Str (default: `''`).
Prefix to use for filenames of saved pictures
(only relevant if `save_to_dir` is set).
save_format: one of "png", "jpeg"
(only relevant if `save_to_dir` is set). Default: "png".
subset: Subset of data (`"training"` or `"validation"`) if
`validation_split` is set in `ImageDataGenerator`.
# Returns
An `Iterator` yielding tuples of `(x, y)`
where `x` is a numpy array of image data
(in the case of a single image input) or a list
of numpy arrays (in the case with
additional inputs) and `y` is a numpy array
of corresponding labels. If 'sample_weight' is not None,
the yielded tuples are of the form `(x, y, sample_weight)`.
If `y` is None, only the numpy array `x` is returned.
"""
return NumpyArrayIterator(
x, y, self,
batch_size=batch_size,
shuffle=shuffle,
sample_weight=sample_weight,
seed=seed,
data_format=self.data_format,
save_to_dir=save_to_dir,
save_prefix=save_prefix,
save_format=save_format,
subset=subset)
def flow_from_directory(self, directory,
target_size=(256, 256), color_mode='rgb',
classes=None, class_mode='categorical',
batch_size=32, shuffle=True, seed=None,
save_to_dir=None,
save_prefix='',
save_format='png',
follow_links=False,
subset=None,
interpolation='nearest'):
"""Takes the path to a directory & generates batches of augmented data.
# Arguments
directory: Path to the target directory.
It should contain one subdirectory per class.
Any PNG, JPG, BMP, PPM or TIF images
inside each of the subdirectories directory tree
will be included in the generator.
See [this script](
https://gist.github.com/fchollet/
0830affa1f7f19fd47b06d4cf89ed44d)
for more details.
target_size: Tuple of integers `(height, width)`,
default: `(256, 256)`.
The dimensions to which all images found will be resized.
color_mode: One of "grayscale", "rbg". Default: "rgb".
Whether the images will be converted to
have 1 or 3 color channels.
classes: Optional list of class subdirectories
(e.g. `['dogs', 'cats']`). Default: None.
If not provided, the list of classes will be automatically
inferred from the subdirectory names/structure
under `directory`, where each subdirectory will
be treated as a different class
(and the order of the classes, which will map to the label
indices, will be alphanumeric).
The dictionary containing the mapping from class names to class
indices can be obtained via the attribute `class_indices`.
class_mode: One of "categorical", "binary", "sparse",
"input", or None. Default: "categorical".
Determines the type of label arrays that are returned:
- "categorical" will be 2D one-hot encoded labels,
- "binary" will be 1D binary labels,
"sparse" will be 1D integer labels,
- "input" will be images identical
to input images (mainly used to work with autoencoders).
- If None, no labels are returned
(the generator will only yield batches of image data,
which is useful to use with `model.predict_generator()`,
`model.evaluate_generator()`, etc.).
Please note that in case of class_mode None,
the data still needs to reside in a subdirectory
of `directory` for it to work correctly.
batch_size: Size of the batches of data (default: 32).
shuffle: Whether to shuffle the data (default: True)
seed: Optional random seed for shuffling and transformations.
save_to_dir: None or str (default: None).
This allows you to optionally specify
a directory to which to save
the augmented pictures being generated
(useful for visualizing what you are doing).
save_prefix: Str. Prefix to use for filenames of saved pictures
(only relevant if `save_to_dir` is set).
save_format: One of "png", "jpeg"
(only relevant if `save_to_dir` is set). Default: "png".
follow_links: Whether to follow symlinks inside
class subdirectories (default: False).
subset: Subset of data (`"training"` or `"validation"`) if
`validation_split` is set in `ImageDataGenerator`.
interpolation: Interpolation method used to
resample the image if the
target size is different from that of the loaded image.
Supported methods are `"nearest"`, `"bilinear"`,
and `"bicubic"`.
If PIL version 1.1.3 or newer is installed, `"lanczos"` is also
supported. If PIL version 3.4.0 or newer is installed,
`"box"` and `"hamming"` are also supported.
By default, `"nearest"` is used.
# Returns
A `DirectoryIterator` yielding tuples of `(x, y)`
where `x` is a numpy array containing a batch
of images with shape `(batch_size, *target_size, channels)`
and `y` is a numpy array of corresponding labels.
"""
return DirectoryIterator(
directory, self,
target_size=target_size, color_mode=color_mode,
classes=classes, class_mode=class_mode,
data_format=self.data_format,
batch_size=batch_size, shuffle=shuffle, seed=seed,
save_to_dir=save_to_dir,
save_prefix=save_prefix,
save_format=save_format,
follow_links=follow_links,
subset=subset,
interpolation=interpolation)
def standardize(self, x):
"""Applies the normalization configuration to a batch of inputs.
# Arguments
x: Batch of inputs to be normalized.
# Returns
The inputs, normalized.
"""
imagenet_mean = np.array([0.485, 0.456, 0.406])
imagenet_std = np.array([0.229, 0.224, 0.225])
if self.rescale:
x *= self.rescale
if self.preprocessing_function:
x = self.preprocessing_function(x)
# if self.rescale:
# x *= self.rescale
if self.samplewise_center:
x -= np.mean(x, keepdims=True)
if self.samplewise_std_normalization:
x /= (np.std(x, keepdims=True) + backend.epsilon())
#x = (x - imagenet_mean) / imagenet_std
if self.featurewise_center:
if self.mean is not None:
x -= self.mean
else:
warnings.warn('This ImageDataGenerator specifies '
'`featurewise_center`, but it hasn\'t '
'been fit on any training data. Fit it '
'first by calling `.fit(numpy_data)`.')
if self.featurewise_std_normalization:
if self.std is not None:
x /= (self.std + backend.epsilon())
else:
warnings.warn('This ImageDataGenerator specifies '
'`featurewise_std_normalization`, '
'but it hasn\'t '
'been fit on any training data. Fit it '
'first by calling `.fit(numpy_data)`.')
if self.zca_whitening:
if self.principal_components is not None:
flatx = np.reshape(x, (-1, np.prod(x.shape[-3:])))
whitex = np.dot(flatx, self.principal_components)
x = np.reshape(whitex, x.shape)
else:
warnings.warn('This ImageDataGenerator specifies '
'`zca_whitening`, but it hasn\'t '
'been fit on any training data. Fit it '
'first by calling ')
# if self.contrast_stretching:
# if np.random.random() < 0.5:
# p2, p98 = np.percentile((x),(2,98))
# x = (exposure.rescale_intensity((x), in_range=(p2, p98)))
# if self.adaptive_equalization:
# if np.random.random() < 0.5:
# x = (exposure.equalize_adapthist((x), clip_limit = 0.03))
# if self.histogram_equalization:
# if np.random.random() < 0.5:
# x = (exposure.equalize_hist((x)))
return x
def get_random_transform(self, img_shape, seed=None):
"""Generates random parameters for a transformation.
# Arguments
seed: Random seed.
img_shape: Tuple of integers.
Shape of the image that is transformed.
# Returns
A dictionary containing randomly chosen parameters describing the
transformation.
"""
img_row_axis = self.row_axis - 1
img_col_axis = self.col_axis - 1
if seed is not None:
np.random.seed(seed)
if self.rotation_range:
theta = np.random.uniform(
-self.rotation_range,
self.rotation_range)
else:
theta = 0
if self.height_shift_range:
try: # 1-D array-like or int
tx = np.random.choice(self.height_shift_range)
tx *= np.random.choice([-1, 1])
except ValueError: # floating point
tx = np.random.uniform(-self.height_shift_range,
self.height_shift_range)
if np.max(self.height_shift_range) < 1:
tx *= img_shape[img_row_axis]
else:
tx = 0
if self.width_shift_range:
try: # 1-D array-like or int
ty = np.random.choice(self.width_shift_range)
ty *= np.random.choice([-1, 1])
except ValueError: # floating point
ty = np.random.uniform(-self.width_shift_range,
self.width_shift_range)
if np.max(self.width_shift_range) < 1:
ty *= img_shape[img_col_axis]
else:
ty = 0
if self.shear_range:
shear = np.random.uniform(
-self.shear_range,
self.shear_range)
else:
shear = 0
if self.zoom_range[0] == 1 and self.zoom_range[1] == 1:
zx, zy = 1, 1
else:
zx, zy = np.random.uniform(
self.zoom_range[0],
self.zoom_range[1],
2)
flip_horizontal = (np.random.random() < 0.5) * self.horizontal_flip
flip_vertical = (np.random.random() < 0.5) * self.vertical_flip
channel_shift_intensity = None
if self.channel_shift_range != 0:
channel_shift_intensity = np.random.uniform(-self.channel_shift_range,
self.channel_shift_range)
brightness = None
if self.brightness_range is not None:
if len(self.brightness_range) != 2:
raise ValueError(
'`brightness_range should be tuple or list of two floats. '
'Received: %s' % brightness_range)
brightness = np.random.uniform(self.brightness_range[0],
self.brightness_range[1])
transform_parameters = {'theta': theta,
'tx': tx,
'ty': ty,
'shear': shear,
'zx': zx,
'zy': zy,
'flip_horizontal': flip_horizontal,
'flip_vertical': flip_vertical,
'channel_shift_intensity': channel_shift_intensity,
'brightness': brightness,
'contrast_stretching' : self.contrast_stretching,
'adaptive_equalization' : self.adaptive_equalization,
'histogram_equalization' : self.histogram_equalization
}
return transform_parameters
def apply_transform(self, x, transform_parameters):
"""Applies a transformation to an image according to given parameters.
# Arguments
x: 3D tensor, single image.
transform_parameters: Dictionary with string - parameter pairs
describing the transformation.
Currently, the following parameters
from the dictionary are used:
- `'theta'`: Float. Rotation angle in degrees.
- `'tx'`: Float. Shift in the x direction.
- `'ty'`: Float. Shift in the y direction.
- `'shear'`: Float. Shear angle in degrees.
- `'zx'`: Float. Zoom in the x direction.
- `'zy'`: Float. Zoom in the y direction.
- `'flip_horizontal'`: Boolean. Horizontal flip.
- `'flip_vertical'`: Boolean. Vertical flip.
- `'channel_shift_intencity'`: Float. Channel shift intensity.
- `'brightness'`: Float. Brightness shift intensity.
# Returns
A ransformed version of the input (same shape).
"""
# x is a single image, so it doesn't have image number at index 0
img_row_axis = self.row_axis - 1
img_col_axis = self.col_axis - 1
img_channel_axis = self.channel_axis - 1
x = apply_affine_transform(x, transform_parameters.get('theta', 0),
transform_parameters.get('tx', 0),
transform_parameters.get('ty', 0),
transform_parameters.get('shear', 0),
transform_parameters.get('zx', 1),
transform_parameters.get('zy', 1),
row_axis=img_row_axis, col_axis=img_col_axis,
channel_axis=img_channel_axis,
fill_mode=self.fill_mode, cval=self.cval)
if transform_parameters.get('channel_shift_intensity') is not None:
x = apply_channel_shift(x,
transform_parameters['channel_shift_intensity'],
img_channel_axis)
if transform_parameters.get('flip_horizontal', False):
x = flip_axis(x, img_col_axis)
if transform_parameters.get('flip_vertical', False):
x = flip_axis(x, img_row_axis)
if transform_parameters.get('brightness') is not None:
x = apply_brightness_shift(x, transform_parameters['brightness'])
if transform_parameters.get('contrast_stretching') is not None:
if np.random.random() < 1.0:
x = img_to_array(x)
p2, p98 = np.percentile((x),(2,98))
x = (exposure.rescale_intensity((x), in_range=(p2, p98)))
# x = x.reshape((x.shape[0], x.shape[1],3))
# if transform_parameters.get('adaptive_equalization') is not None:
# if np.random.random() < 1.0:
# x = (exposure.equalize_adapthist(x/255, clip_limit = 0.03))
# x = x.reshape((x.shape[0], x.shape[1],1))
if transform_parameters.get('histogram_equalization') is not None:
if np.random.random() < 1.0:
x[:,:,0] = exposure.equalize_hist(x[:,:,0])
x[:,:,1] = exposure.equalize_hist(x[:,:,1])
x[:,:,2] = exposure.equalize_hist(x[:,:,2])
# x = x.reshape((x.shape[0], x.shape[1],3))
# x = x.reshape((x.shape[0], x.shape[1], 1))
return x
def random_transform(self, x, seed=None):
"""Applies a random transformation to an image.
# Arguments
x: 3D tensor, single image.
seed: Random seed.
# Returns
A randomly transformed version of the input (same shape).
"""
params = self.get_random_transform(x.shape, seed)
return self.apply_transform(x, params)
def fit(self, x,
augment=False,
rounds=1,
seed=None):
"""Fits the data generator to some sample data.
This computes the internal data stats related to the
data-dependent transformations, based on an array of sample data.
Only required if `featurewise_center` or
`featurewise_std_normalization` or `zca_whitening` are set to True.
# Arguments
x: Sample data. Should have rank 4.
In case of grayscale data,
the channels axis should have value 1, and in case
of RGB data, it should have value 3.
augment: Boolean (default: False).
Whether to fit on randomly augmented samples.
rounds: Int (default: 1).
If using data augmentation (`augment=True`),
this is how many augmentation passes over the data to use.
seed: Int (default: None). Random seed.
"""
x = np.asarray(x, dtype=backend.floatx())
if x.ndim != 4:
raise ValueError('Input to `.fit()` should have rank 4. '
'Got array with shape: ' + str(x.shape))
if x.shape[self.channel_axis] not in {1, 3, 4}:
warnings.warn(
'Expected input to be images (as Numpy array) '
'following the data format convention "' +
self.data_format + '" (channels on axis ' +
str(self.channel_axis) + '), i.e. expected '
'either 1, 3 or 4 channels on axis ' +
str(self.channel_axis) + '. '
'However, it was passed an array with shape ' +
str(x.shape) + ' (' + str(x.shape[self.channel_axis]) +
' channels).')
if seed is not None:
np.random.seed(seed)
x = np.copy(x)
if augment:
ax = np.zeros(
tuple([rounds * x.shape[0]] + list(x.shape)[1:]),
dtype=backend.floatx())
for r in range(rounds):
for i in range(x.shape[0]):
ax[i + r * x.shape[0]] = self.random_transform(x[i])
x = ax
if self.featurewise_center:
self.mean = np.mean(x, axis=(0, self.row_axis, self.col_axis))
broadcast_shape = [1, 1, 1]
broadcast_shape[self.channel_axis - 1] = x.shape[self.channel_axis]
self.mean = np.reshape(self.mean, broadcast_shape)
x -= self.mean
if self.featurewise_std_normalization:
self.std = np.std(x, axis=(0, self.row_axis, self.col_axis))
broadcast_shape = [1, 1, 1]
broadcast_shape[self.channel_axis - 1] = x.shape[self.channel_axis]
self.std = np.reshape(self.std, broadcast_shape)
x /= (self.std + backend.epsilon())
if self.zca_whitening:
flat_x = np.reshape(
x, (x.shape[0], x.shape[1] * x.shape[2] * x.shape[3]))
sigma = np.dot(flat_x.T, flat_x) / flat_x.shape[0]
u, s, _ = linalg.svd(sigma)
s_inv = 1. / np.sqrt(s[np.newaxis] + self.zca_epsilon)
self.principal_components = (u * s_inv).dot(u.T)
class Iterator(keras_utils.Sequence):
"""Base class for image data iterators.
Every `Iterator` must implement the `_get_batches_of_transformed_samples`
method.
# Arguments
n: Integer, total number of samples in the dataset to loop over.
batch_size: Integer, size of a batch.
shuffle: Boolean, whether to shuffle the data between epochs.
seed: Random seeding for data shuffling.
"""
def __init__(self, n, batch_size, shuffle, seed):
self.n = n
self.batch_size = batch_size
self.seed = seed
self.shuffle = shuffle
self.batch_index = 0
self.total_batches_seen = 0
self.lock = threading.Lock()
self.index_array = None
self.index_generator = self._flow_index()
def _set_index_array(self):
self.index_array = np.arange(self.n)
if self.shuffle:
self.index_array = np.random.permutation(self.n)
def __getitem__(self, idx):
if idx >= len(self):
raise ValueError('Asked to retrieve element {idx}, '
'but the Sequence '
'has length {length}'.format(idx=idx,
length=len(self)))
if self.seed is not None:
np.random.seed(self.seed + self.total_batches_seen)
self.total_batches_seen += 1
if self.index_array is None:
self._set_index_array()
index_array = self.index_array[self.batch_size * idx:
self.batch_size * (idx + 1)]
return self._get_batches_of_transformed_samples(index_array)
def __len__(self):
return (self.n + self.batch_size - 1) // self.batch_size # round up
def on_epoch_end(self):
self._set_index_array()
def reset(self):
self.batch_index = 0
def _flow_index(self):
# Ensure self.batch_index is 0.
self.reset()
while 1:
if self.seed is not None:
np.random.seed(self.seed + self.total_batches_seen)
if self.batch_index == 0:
self._set_index_array()
current_index = (self.batch_index * self.batch_size) % self.n
if self.n > current_index + self.batch_size:
self.batch_index += 1
else:
self.batch_index = 0
self.total_batches_seen += 1
yield self.index_array[current_index:
current_index + self.batch_size]
def __iter__(self):
# Needed if we want to do something like:
# for x, y in data_gen.flow(...):
return self
def __next__(self, *args, **kwargs):
return self.next(*args, **kwargs)
def _get_batches_of_transformed_samples(self, index_array):
"""Gets a batch of transformed samples.
# Arguments
index_array: Array of sample indices to include in batch.
# Returns
A batch of transformed samples.
"""
raise NotImplementedError
class NumpyArrayIterator(Iterator):
"""Iterator yielding data from a Numpy array.
# Arguments
x: Numpy array of input data or tuple.
If tuple, the second elements is either
another numpy array or a list of numpy arrays,
each of which gets passed
through as an output without any modifications.
y: Numpy array of targets data.
image_data_generator: Instance of `ImageDataGenerator`
to use for random transformations and normalization.
batch_size: Integer, size of a batch.
shuffle: Boolean, whether to shuffle the data between epochs.
sample_weight: Numpy array of sample weights.
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).
subset: Subset of data (`"training"` or `"validation"`) if
validation_split is set in ImageDataGenerator.
"""
def __init__(self, x, y, image_data_generator,
batch_size=32, shuffle=False, sample_weight=None,
seed=None, data_format=None,
save_to_dir=None, save_prefix='', save_format='png',
subset=None):
if (type(x) is tuple) or (type(x) is list):
if type(x[1]) is not list:
x_misc = [np.asarray(x[1])]
else:
x_misc = [np.asarray(xx) for xx in x[1]]
x = x[0]
for xx in x_misc:
if len(x) != len(xx):
raise ValueError(
'All of the arrays in `x` '
'should have the same length. '
'Found a pair with: len(x[0]) = %s, len(x[?]) = %s' %
(len(x), len(xx)))
else:
x_misc = []
if y is not None and len(x) != len(y):
raise ValueError('`x` (images tensor) and `y` (labels) '
'should have the same length. '
'Found: x.shape = %s, y.shape = %s' %
(np.asarray(x).shape, np.asarray(y).shape))
if sample_weight is not None and len(x) != len(sample_weight):
raise ValueError('`x` (images tensor) and `sample_weight` '
'should have the same length. '
'Found: x.shape = %s, sample_weight.shape = %s' %
(np.asarray(x).shape, np.asarray(sample_weight).shape))
if subset is not None:
if subset not in {'training', 'validation'}:
raise ValueError('Invalid subset name:', subset,
'; expected "training" or "validation".')
split_idx = int(len(x) * image_data_generator._validation_split)
if subset == 'validation':
x = x[:split_idx]
x_misc = [np.asarray(xx[:split_idx]) for xx in x_misc]
if y is not None:
y = y[:split_idx]
else:
x = x[split_idx:]
x_misc = [np.asarray(xx[split_idx:]) for xx in x_misc]
if y is not None:
y = y[split_idx:]
if data_format is None:
data_format = backend.image_data_format()
self.x = np.asarray(x, dtype=backend.floatx())
self.x_misc = x_misc
if self.x.ndim != 4:
raise ValueError('Input data in `NumpyArrayIterator` '
'should have rank 4. You passed an array '
'with shape', self.x.shape)
channels_axis = 3 if data_format == 'channels_last' else 1
if self.x.shape[channels_axis] not in {1, 3, 4}:
warnings.warn('NumpyArrayIterator is set to use the '
'data format convention "' + data_format + '" '
'(channels on axis ' + str(channels_axis) +
'), i.e. expected either 1, 3 or 4 '
'channels on axis ' + str(channels_axis) + '. '
'However, it was passed an array with shape ' +
str(self.x.shape) + ' (' +
str(self.x.shape[channels_axis]) + ' channels).')
if y is not None:
self.y = np.asarray(y)
else:
self.y = None
if sample_weight is not None:
self.sample_weight = np.asarray(sample_weight)
else:
self.sample_weight = None
self.image_data_generator = image_data_generator
self.data_format = data_format
self.save_to_dir = save_to_dir
self.save_prefix = save_prefix
self.save_format = save_format
super(NumpyArrayIterator, self).__init__(x.shape[0],
batch_size,
shuffle,
seed)
def _get_batches_of_transformed_samples(self, index_array):
batch_x = np.zeros(tuple([len(index_array)] + list(self.x.shape)[1:]),
dtype=backend.floatx())
for i, j in enumerate(index_array):
x = self.x[j]
params = self.image_data_generator.get_random_transform(x.shape)
x = self.image_data_generator.apply_transform(
x.astype(backend.floatx()), params)
x = self.image_data_generator.standardize(x)
batch_x[i] = x
if self.save_to_dir:
for i, j in enumerate(index_array):
img = array_to_img(batch_x[i], self.data_format, scale=True)
fname = '{prefix}_{index}_{hash}.{format}'.format(
prefix=self.save_prefix,
index=j,
hash=np.random.randint(1e4),
format=self.save_format)
img.save(os.path.join(self.save_to_dir, fname))
batch_x_miscs = [xx[index_array] for xx in self.x_misc]
output = (batch_x if batch_x_miscs == []
else [batch_x] + batch_x_miscs,)
if self.y is None:
return output[0]
output += (self.y[index_array],)
if self.sample_weight is not None:
output += (self.sample_weight[index_array],)
return output
def next(self):
"""For python 2.x.
# Returns
The next batch.
"""
# Keeps under lock only the mechanism which advances
# the indexing of each batch.
with self.lock:
index_array = next(self.index_generator)
# The transformation of images is not under thread lock
# so it can be done in parallel
return self._get_batches_of_transformed_samples(index_array)
def _iter_valid_files(directory, white_list_formats, follow_links):
"""Iterates on files with extension in `white_list_formats` contained in `directory`.
# Arguments
directory: Absolute path to the directory
containing files to be counted
white_list_formats: Set of strings containing allowed extensions for
the files to be counted.
follow_links: Boolean.
# Yields
Tuple of (root, filename) with extension in `white_list_formats`.
"""
def _recursive_list(subpath):
return sorted(os.walk(subpath, followlinks=follow_links),
key=lambda x: x[0])
for root, _, files in _recursive_list(directory):
for fname in sorted(files):
for extension in white_list_formats:
if fname.lower().endswith('.tiff'):
warnings.warn('Using \'.tiff\' files with multiple bands '
'will cause distortion. '
'Please verify your output.')
if fname.lower().endswith('.' + extension):
yield root, fname
def _count_valid_files_in_directory(directory,
white_list_formats,
split,
follow_links):
"""Counts files with extension in `white_list_formats` contained in `directory`.
# Arguments
directory: absolute path to the directory
containing files to be counted
white_list_formats: set of strings containing allowed extensions for
the files to be counted.
split: tuple of floats (e.g. `(0.2, 0.6)`) to only take into
account a certain fraction of files in each directory.
E.g.: `segment=(0.6, 1.0)` would only account for last 40 percent
of images in each directory.
follow_links: boolean.
# Returns
the count of files with extension in `white_list_formats` contained in
the directory.
"""
num_files = len(list(
_iter_valid_files(directory, white_list_formats, follow_links)))
if split:
start, stop = int(split[0] * num_files), int(split[1] * num_files)
else:
start, stop = 0, num_files
return stop - start
def _list_valid_filenames_in_directory(directory, white_list_formats, split,
class_indices, follow_links):
"""Lists paths of files in `subdir` with extensions in `white_list_formats`.
# Arguments
directory: absolute path to a directory containing the files to list.
The directory name is used as class label
and must be a key of `class_indices`.
white_list_formats: set of strings containing allowed extensions for
the files to be counted.
split: tuple of floats (e.g. `(0.2, 0.6)`) to only take into
account a certain fraction of files in each directory.
E.g.: `segment=(0.6, 1.0)` would only account for last 40 percent
of images in each directory.
class_indices: dictionary mapping a class name to its index.
follow_links: boolean.
# Returns
classes: a list of class indices
filenames: the path of valid files in `directory`, relative from
`directory`'s parent (e.g., if `directory` is "dataset/class1",
the filenames will be
`["class1/file1.jpg", "class1/file2.jpg", ...]`).
"""
dirname = os.path.basename(directory)
if split:
num_files = len(list(
_iter_valid_files(directory, white_list_formats, follow_links)))
start, stop = int(split[0] * num_files), int(split[1] * num_files)
valid_files = list(
_iter_valid_files(
directory, white_list_formats, follow_links))[start: stop]
else:
valid_files = _iter_valid_files(
directory, white_list_formats, follow_links)
classes = []
filenames = []
for root, fname in valid_files:
classes.append(class_indices[dirname])
absolute_path = os.path.join(root, fname)
relative_path = os.path.join(
dirname, os.path.relpath(absolute_path, directory))
filenames.append(relative_path)
return classes, filenames
class DirectoryIterator(Iterator):
"""Iterator capable of reading images from a directory on disk.
# 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 subdirectories
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,
`"input"`: targets are images identical to input images (mainly
used to work with autoencoders),
`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).
subset: Subset of data (`"training"` or `"validation"`) if
validation_split is set in ImageDataGenerator.
interpolation: Interpolation method used to resample the image if the
target size is different from that of the loaded image.
Supported methods are "nearest", "bilinear", and "bicubic".
If PIL version 1.1.3 or newer is installed, "lanczos" is also
supported. If PIL version 3.4.0 or newer is installed, "box" and
"hamming" are also supported. By default, "nearest" is used.
"""
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='png',
follow_links=False,
subset=None,
interpolation='nearest'):
if data_format is None:
data_format = backend.image_data_format()
self.directory = directory
self.image_data_generator = image_data_generator
self.target_size = tuple(target_size)
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',
'input', None}:
raise ValueError('Invalid class_mode:', class_mode,
'; expected one of "categorical", '
'"binary", "sparse", "input"'
' or None.')
self.class_mode = class_mode
self.save_to_dir = save_to_dir
self.save_prefix = save_prefix
self.save_format = save_format
self.interpolation = interpolation
if subset is not None:
validation_split = self.image_data_generator._validation_split
if subset == 'validation':
split = (0, validation_split)
elif subset == 'training':
split = (validation_split, 1)
else:
raise ValueError('Invalid subset name: ', subset,
'; expected "training" or "validation"')
else:
split = None
self.subset = subset
white_list_formats = {'png', 'jpg', 'jpeg', 'bmp',
'ppm', 'tif', 'tiff'}
# 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_classes = len(classes)
self.class_indices = dict(zip(classes, range(len(classes))))
pool = multiprocessing.pool.ThreadPool()
function_partial = partial(_count_valid_files_in_directory,
white_list_formats=white_list_formats,
follow_links=follow_links,
split=split)
self.samples = sum(pool.map(function_partial,
(os.path.join(directory, subdir)
for subdir in classes)))
print('Found %d images belonging to %d classes.' %
(self.samples, self.num_classes))
# Second, build an index of the images
# in the different class subfolders.
results = []
self.filenames = []
self.classes = np.zeros((self.samples,), dtype='int32')
i = 0
for dirpath in (os.path.join(directory, subdir) for subdir in classes):
results.append(
pool.apply_async(_list_valid_filenames_in_directory,
(dirpath, white_list_formats, split,
self.class_indices, follow_links)))
for res in results:
classes, filenames = res.get()
self.classes[i:i + len(classes)] = classes
self.filenames += filenames
i += len(classes)
pool.close()
pool.join()
super(DirectoryIterator, self).__init__(self.samples,
batch_size,
shuffle,
seed)
def _get_batches_of_transformed_samples(self, index_array):
batch_x = np.zeros(
(len(index_array),) + self.image_shape,
dtype=backend.floatx())
grayscale = self.color_mode == 'grayscale'
# build batch of image data
for i, j in enumerate(index_array):
fname = self.filenames[j]
img = load_img(os.path.join(self.directory, fname),
grayscale=grayscale,
target_size=self.target_size,
interpolation=self.interpolation)
x = img_to_array(img, data_format=self.data_format)
params = self.image_data_generator.get_random_transform(x.shape)
x = self.image_data_generator.apply_transform(x, params)
x = self.image_data_generator.standardize(x)
batch_x[i] = x
# optionally save augmented images to disk for debugging purposes
if self.save_to_dir:
for i, j in enumerate(index_array):
img = array_to_img(batch_x[i], self.data_format, scale=True)
fname = '{prefix}_{index}_{hash}.{format}'.format(
prefix=self.save_prefix,
index=j,
hash=np.random.randint(1e7),
format=self.save_format)
img.save(os.path.join(self.save_to_dir, fname))
# build batch of labels
if self.class_mode == 'input':
batch_y = batch_x.copy()
elif self.class_mode == 'sparse':
batch_y = self.classes[index_array]
elif self.class_mode == 'binary':
batch_y = self.classes[index_array].astype(backend.floatx())
elif self.class_mode == 'categorical':
batch_y = np.zeros(
(len(batch_x), self.num_classes),
dtype=backend.floatx())
for i, label in enumerate(self.classes[index_array]):
batch_y[i, label] = 1.
else:
return batch_x
return batch_x, batch_y
def next(self):
"""For python 2.x.
# Returns
The next batch.
"""
with self.lock:
index_array = next(self.index_generator)
# The transformation of images is not under thread lock
# so it can be done in parallel
return self._get_batches_of_transformed_samples(index_array)
Datasets
Models
