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image.py
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image.py
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"""Fairly basic set of tools for real-time data augmentation on image data.
Can easily be extended to include new transformations,
new preprocessing methods, etc...
"""
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
from functools import partial
import pandas as pd
from .. import backend as K
from ..utils.data_utils import Sequence
import h5py as h5
import h5py_cache as h5c
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,
}
# 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 matrix_random_crop(batch_x, imgs, random_crop_size):
# Note: image_data_format is 'channel_last'
#assert img.shape[2] == 3
batch_size, height, width = imgs.shape[0], imgs.shape[1], img.shape[2]
dy, dx = random_crop_size
xs = np.random.randint(0, width - dx + 1, batch_size)
ys = np.random.randint(0, height - dy + 1, batch_size)
for index in range(len(batch_x)):
batch_x[index, :, :] = imgs[index,ys[index]:ys[index]+dy, xs[index]:xs[index]+ds,:]
return batch_x
def random_crop(img, random_crop_size):
# Note: image_data_format is 'channel_last'
#assert img.shape[2] == 3
height, width = img.shape[0], img.shape[1]
dy, dx = random_crop_size
x = np.random.randint(0, width - dx + 1)
y = np.random.randint(0, height - dy + 1)
return img[y:(y+dy), x:(x+dx), :]
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.deg2rad(np.random.uniform(-rg, rg))
rotation_matrix = np.array([[np.cos(theta), -np.sin(theta), 0],
[np.sin(theta), np.cos(theta), 0],
[0, 0, 1]])
h, w = x.shape[row_axis], x.shape[col_axis]
transform_matrix = transform_matrix_offset_center(rotation_matrix, h, w)
x = apply_transform(x, transform_matrix, channel_axis, fill_mode, 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
translation_matrix = np.array([[1, 0, tx],
[0, 1, ty],
[0, 0, 1]])
transform_matrix = translation_matrix # no need to do offset
x = apply_transform(x, transform_matrix, channel_axis, fill_mode, 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.deg2rad(np.random.uniform(-intensity, intensity))
shear_matrix = np.array([[1, -np.sin(shear), 0],
[0, np.cos(shear), 0],
[0, 0, 1]])
h, w = x.shape[row_axis], x.shape[col_axis]
transform_matrix = transform_matrix_offset_center(shear_matrix, h, w)
x = apply_transform(x, transform_matrix, channel_axis, fill_mode, 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 arg: ', 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)
zoom_matrix = np.array([[zx, 0, 0],
[0, zy, 0],
[0, 0, 1]])
h, w = x.shape[row_axis], x.shape[col_axis]
transform_matrix = transform_matrix_offset_center(zoom_matrix, h, w)
x = apply_transform(x, transform_matrix, channel_axis, fill_mode, cval)
return x
def random_channel_shift(x, intensity, channel_axis=0):
"""Perform a random 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 + np.random.uniform(-intensity, 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_brightness(x, brightness_range):
"""Perform 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 arg: ', brightness_range)
x = array_to_img(x)
x = imgenhancer_Brightness = ImageEnhance.Brightness(x)
u = np.random.uniform(brightness_range[0], brightness_range[1])
x = imgenhancer_Brightness.enhance(u)
x = img_to_array(x)
return x
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_transform(x,
transform_matrix,
channel_axis=0,
fill_mode='nearest',
cval=0.):
"""Apply the image transformation specified by a matrix.
# Arguments
x: 2D numpy array, single image.
transform_matrix: Numpy array specifying the geometric transformation.
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
The transformed version of the input.
"""
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 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.
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=K.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 = K.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.
# Returns
A 3D Numpy array.
# Raises
ValueError: if invalid `img` or `data_format` is passed.
"""
if data_format is None:
data_format = K.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=K.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 load_img(path, grayscale=False, target_size=None,
interpolation='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)]
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).
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: One of {"channels_first", "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,
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,
apply_gen_transform = False):
if data_format is None:
data_format = K.image_data_format()
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
self.apply_gen_transform = apply_gen_transform
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 arg: ', 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 arg: ', 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 arg: ', 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, seed=None,
save_to_dir=None, save_prefix='', save_format='png', subset=None):
"""Takes numpy data & label arrays, and generates batches of
augmented/normalized data.
# Arguments
x: 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.
y: labels.
batch_size: int (default: 32).
shuffle: boolean (default: True).
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 and
`y` is a numpy array of corresponding labels."""
return NumpyArrayIterator(
x, y, self,
batch_size=batch_size,
shuffle=shuffle,
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_hdf5(self, x, y=None, batch_size=32, shuffle=False, crop = False, crop_size=(224,224), seed=None,
save_to_dir=None, save_prefix='', save_format='png', subset=None):
"""Takes HDF5Matrix data & label arrays, and generates batches of
augmented/normalized data.
# Arguments
x: 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.
y: labels.
batch_size: int (default: 32).
shuffle: boolean (default: True).
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 HDF5Matrix array of image data and
`y` is a HDF5Matrix array of corresponding labels."""
return HDF5MatrixCacheIterator(
x, y, self,
batch_size=batch_size,
shuffle=shuffle,
crop = crop,
crop_size = crop_size,
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), crop_size = (224,224),color_mode='rgb',
classes=None, class_mode='categorical',
batch_size=32, shuffle=True, crop=False,seed=None,
save_to_dir=None,
save_prefix='',
save_format='png',
follow_links=False,
subset=None,
interpolation='nearest',
table_pd = None,
test_pd = None):
"""Takes the path to a directory, and generates batches of augmented/normalized 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
`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, crop_size = crop_size, color_mode=color_mode,
classes=classes, class_mode=class_mode,
data_format=self.data_format,
batch_size=batch_size, shuffle=shuffle, crop=crop,seed=seed,
save_to_dir=save_to_dir,
save_prefix=save_prefix,
save_format=save_format,
follow_links=follow_links,
subset=subset,
interpolation=interpolation,
table_pd=table_pd,
test_pd = test_pd)
def standardize(self, x):
"""Apply the normalization configuration to a batch of inputs.
# Arguments
x: batch of inputs to be normalized.
# Returns
The inputs, normalized.
"""
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) + K.epsilon())
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 + K.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 `.fit(numpy_data)`.')
return x
def random_transform(self, x, seed=None):
"""Randomly augment a single image tensor.
# Arguments
x: 3D tensor, single image.
seed: random seed.
# Returns
A randomly transformed 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
if seed is not None:
np.random.seed(seed)
# use composition of homographies
# to generate final transform that needs to be applied
if self.rotation_range:
theta = np.deg2rad(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 *= x.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 *= x.shape[img_col_axis]
else:
ty = 0
if self.shear_range:
shear = np.deg2rad(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)
transform_matrix = None
if theta != 0:
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]])
transform_matrix = shift_matrix if transform_matrix is None else np.dot(transform_matrix, shift_matrix)
if shear != 0:
shear_matrix = np.array([[1, -np.sin(shear), 0],
[0, np.cos(shear), 0],
[0, 0, 1]])
transform_matrix = shear_matrix if transform_matrix is None else 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]])
transform_matrix = zoom_matrix if transform_matrix is None else np.dot(transform_matrix, zoom_matrix)
if transform_matrix is not None:
h, w = x.shape[img_row_axis], x.shape[img_col_axis]
transform_matrix = transform_matrix_offset_center(transform_matrix, h, w)
x = apply_transform(x, transform_matrix, img_channel_axis,
fill_mode=self.fill_mode, cval=self.cval)
if self.channel_shift_range != 0:
x = random_channel_shift(x,
self.channel_shift_range,
img_channel_axis)
if self.horizontal_flip:
if np.random.random() < 0.5:
x = flip_axis(x, img_col_axis)
if self.vertical_flip:
if np.random.random() < 0.5:
x = flip_axis(x, img_row_axis)
if self.brightness_range is not None:
x = random_brightness(x, self.brightness_range)
return x
def fit(self, x,
augment=False,
rounds=1,
seed=None):
"""Compute the internal data stats related to the data-dependent transformations, based on an array of sample data.