import numpy as np
import scipy
import scipy.ndimage
from scipy.ndimage.filters import gaussian_filter
from scipy.ndimage.interpolation import map_coordinates
import collections
from PIL import Image
import numbers
import random
__author__ = "Sheng Liu"
__license__ = "GPL"
__version__ = "0.1.0"
__status__ = "Development"
def center_crop(x, center_crop_size):
assert x.ndim == 3
centerw, centerh = x.shape[1] // 2, x.shape[2] // 2
halfw, halfh = center_crop_size[0] // 2, center_crop_size[1] // 2
return x[:, centerw - halfw:centerw + halfw, centerh - halfh:centerh + halfh]
def to_tensor(x):
import torch
x = x.transpose((2, 0, 1))
return torch.from_numpy(x).float()
def random_num_generator(config, random_state=np.random):
if config[0] == 'uniform':
ret = random_state.uniform(config[1], config[2], 1)[0]
elif config[0] == 'lognormal':
ret = random_state.lognormal(config[1], config[2], 1)[0]
else:
print(config)
raise Exception('unsupported format')
return ret
def poisson_downsampling(image, peak, random_state=np.random):
if not isinstance(image, np.ndarray):
imgArr = np.array(image, dtype='float32')
else:
imgArr = image.astype('float32')
Q = imgArr.max(axis=(0, 1)) / peak
if Q[0] == 0:
return imgArr
ima_lambda = imgArr / Q
noisy_img = random_state.poisson(lam=ima_lambda)
return noisy_img.astype('float32')
def elastic_transform(image, alpha=1000, sigma=30, spline_order=1, mode='nearest', random_state=np.random):
"""Elastic deformation of image as described in [Simard2003]_.
.. [Simard2003] Simard, Steinkraus and Platt, "Best Practices for
Convolutional Neural Networks applied to Visual Document Analysis", in
Proc. of the International Conference on Document Analysis and
Recognition, 2003.
"""
assert image.ndim == 3
shape = image.shape[:2]
dx = gaussian_filter((random_state.rand(*shape) * 2 - 1),
sigma, mode="constant", cval=0) * alpha
dy = gaussian_filter((random_state.rand(*shape) * 2 - 1),
sigma, mode="constant", cval=0) * alpha
x, y = np.meshgrid(np.arange(shape[0]), np.arange(shape[1]), indexing='ij')
indices = [np.reshape(x + dx, (-1, 1)), np.reshape(y + dy, (-1, 1))]
result = np.empty_like(image)
for i in range(image.shape[2]):
result[:, :, i] = map_coordinates(
image[:, :, i], indices, order=spline_order, mode=mode).reshape(shape)
return result
class Merge(object):
"""Merge a group of images
"""
def __init__(self, axis=-1):
self.axis = axis
def __call__(self, images):
if isinstance(images, collections.Sequence) or isinstance(images, np.ndarray):
assert all([isinstance(i, np.ndarray)
for i in images]), 'only numpy array is supported'
shapes = [list(i.shape) for i in images]
for s in shapes:
s[self.axis] = None
assert all([s == shapes[0] for s in shapes]
), 'shapes must be the same except the merge axis'
return np.concatenate(images, axis=self.axis)
else:
raise Exception("obj is not a sequence (list, tuple, etc)")
class Split(object):
"""Split images into individual arraies
"""
def __init__(self, *slices, **kwargs):
assert isinstance(slices, collections.Sequence)
slices_ = []
for s in slices:
if isinstance(s, collections.Sequence):
slices_.append(slice(*s))
else:
slices_.append(s)
assert all([isinstance(s, slice) for s in slices_]
), 'slices must be consist of slice instances'
self.slices = slices_
self.axis = kwargs.get('axis', -1)
def __call__(self, image):
if isinstance(image, np.ndarray):
ret = []
for s in self.slices:
sl = [slice(None)] * image.ndim
sl[self.axis] = s
ret.append(image[sl])
return ret
else:
raise Exception("obj is not an numpy array")
class ElasticTransform(object):
"""Apply elastic transformation on a numpy.ndarray (H x W x C)
"""
def __init__(self, alpha, sigma):
self.alpha = alpha
self.sigma = sigma
def __call__(self, image):
if isinstance(self.alpha, collections.Sequence):
alpha = random_num_generator(self.alpha)
else:
alpha = self.alpha
if isinstance(self.sigma, collections.Sequence):
sigma = random_num_generator(self.sigma)
else:
sigma = self.sigma
return elastic_transform(image, alpha=alpha, sigma=sigma)
class PoissonSubsampling(object):
"""Poisson subsampling on a numpy.ndarray (H x W x C)
"""
def __init__(self, peak, random_state=np.random):
self.peak = peak
self.random_state = random_state
def __call__(self, image):
if isinstance(self.peak, collections.Sequence):
peak = random_num_generator(
self.peak, random_state=self.random_state)
else:
peak = self.peak
return poisson_downsampling(image, peak, random_state=self.random_state)
class AddGaussianNoise(object):
"""Add gaussian noise to a numpy.ndarray (H x W x C)
"""
def __init__(self, mean, sigma, random_state=np.random):
self.sigma = sigma
self.mean = mean
self.random_state = random_state
def __call__(self, image):
if isinstance(self.sigma, collections.Sequence):
sigma = random_num_generator(
self.sigma, random_state=self.random_state)
else:
sigma = self.sigma
if isinstance(self.mean, collections.Sequence, random_state=self.random_state):
mean = random_num_generator(self.mean)
else:
mean = self.mean
row, col, ch = image.shape
gauss = self.random_state.normal(mean, sigma, (row, col, ch))
gauss = gauss.reshape(row, col, ch)
image += gauss
return image
class AddSpeckleNoise(object):
"""Add speckle noise to a numpy.ndarray (H x W x C)
"""
def __init__(self, mean, sigma, random_state=np.random):
self.sigma = sigma
self.mean = mean
self.random_state = random_state
def __call__(self, image):
if isinstance(self.sigma, collections.Sequence):
sigma = random_num_generator(
self.sigma, random_state=self.random_state)
else:
sigma = self.sigma
if isinstance(self.mean, collections.Sequence):
mean = random_num_generator(
self.mean, random_state=self.random_state)
else:
mean = self.mean
row, col, ch = image.shape
gauss = self.random_state.normal(mean, sigma, (row, col, ch))
gauss = gauss.reshape(row, col, ch)
image += image * gauss
return image
class RandomGaussianBlurring(object):
"""Apply gaussian blur to a numpy.ndarray (H x W x C)
"""
def __init__(self, sigma, p=0.2, random_state=np.random):
self.sigma = sigma
self.p = p
self.random_state = random_state
def __call__(self, image):
if isinstance(self.sigma, collections.Sequence):
sigma = random_num_generator(
self.sigma, random_state=self.random_state)
else:
sigma = self.sigma
if random.random() < self.p:
image = gaussian_filter(image, sigma=(sigma, sigma, 0))
return image
class AddGaussianPoissonNoise(object):
"""Add poisson noise with gaussian blurred image to a numpy.ndarray (H x W x C)
"""
def __init__(self, sigma, peak, random_state=np.random):
self.sigma = sigma
self.peak = peak
self.random_state = random_state
def __call__(self, image):
if isinstance(self.sigma, collections.Sequence):
sigma = random_num_generator(
self.sigma, random_state=self.random_state)
else:
sigma = self.sigma
if isinstance(self.peak, collections.Sequence):
peak = random_num_generator(
self.peak, random_state=self.random_state)
else:
peak = self.peak
bg = gaussian_filter(image, sigma=(sigma, sigma, 0))
bg = poisson_downsampling(
bg, peak=peak, random_state=self.random_state)
return image + bg
class MaxScaleNumpy(object):
"""scale with max and min of each channel of the numpy array i.e.
channel = (channel - mean) / std
"""
def __init__(self, range_min=0.0, range_max=1.0):
self.scale = (range_min, range_max)
def __call__(self, image):
mn = image.min(axis=(0, 1))
mx = image.max(axis=(0, 1))
return self.scale[0] + (image - mn) * (self.scale[1] - self.scale[0]) / (mx - mn)
class MedianScaleNumpy(object):
"""Scale with median and mean of each channel of the numpy array i.e.
channel = (channel - mean) / std
"""
def __init__(self, range_min=0.0, range_max=1.0):
self.scale = (range_min, range_max)
def __call__(self, image):
mn = image.min(axis=(0, 1))
md = np.median(image, axis=(0, 1))
return self.scale[0] + (image - mn) * (self.scale[1] - self.scale[0]) / (md - mn)
class NormalizeNumpy(object):
"""Normalize each channel of the numpy array i.e.
channel = (channel - mean) / std
"""
def __call__(self, image):
image -= image.mean(axis=(0, 1))
s = image.std(axis=(0, 1))
s[s == 0] = 1.0
image /= s
return image
class MutualExclude(object):
"""Remove elements from one channel
"""
def __init__(self, exclude_channel, from_channel):
self.from_channel = from_channel
self.exclude_channel = exclude_channel
def __call__(self, image):
mask = image[:, :, self.exclude_channel] > 0
image[:, :, self.from_channel][mask] = 0
return image
class RandomCropNumpy(object):
"""Crops the given numpy array at a random location to have a region of
the given size. size can be a tuple (target_height, target_width)
or an integer, in which case the target will be of a square shape (size, size)
"""
def __init__(self, size, random_state=np.random):
if isinstance(size, numbers.Number):
self.size = (int(size), int(size))
else:
self.size = size
self.random_state = random_state
def __call__(self, img):
w, h = img.shape[:2]
th, tw = self.size
if w == tw and h == th:
return img
x1 = self.random_state.randint(0, w - tw)
y1 = self.random_state.randint(0, h - th)
return img[x1:x1 + tw, y1: y1 + th, :]
class CenterCropNumpy(object):
"""Crops the given numpy array at the center to have a region of
the given size. size can be a tuple (target_height, target_width)
or an integer, in which case the target will be of a square shape (size, size)
"""
def __init__(self, size):
if isinstance(size, numbers.Number):
self.size = (int(size), int(size))
else:
self.size = size
def __call__(self, img):
w, h = img.shape[:2]
th, tw = self.size
x1 = int(round((w - tw) / 2.))
y1 = int(round((h - th) / 2.))
return img[x1:x1 + tw, y1: y1 + th, :]
class RandomRotate(object):
"""Rotate a PIL.Image or numpy.ndarray (H x W x C) randomly
"""
def __init__(self, angle_range=(0.0, 360.0), axes=(0, 1), mode='reflect', random_state=np.random):
assert isinstance(angle_range, tuple)
self.angle_range = angle_range
self.random_state = random_state
self.axes = axes
self.mode = mode
def __call__(self, image):
angle = self.random_state.uniform(
self.angle_range[0], self.angle_range[1])
if isinstance(image, np.ndarray):
mi, ma = image.min(), image.max()
image = scipy.ndimage.interpolation.rotate(
image, angle, reshape=False, axes=self.axes, mode=self.mode)
return np.clip(image, mi, ma)
elif isinstance(image, Image.Image):
return image.rotate(angle)
else:
raise Exception('unsupported type')
class BilinearResize(object):
"""Resize a PIL.Image or numpy.ndarray (H x W x C)
"""
def __init__(self, zoom):
self.zoom = [zoom, zoom, 1]
def __call__(self, image):
if isinstance(image, np.ndarray):
return scipy.ndimage.interpolation.zoom(image, self.zoom)
elif isinstance(image, Image.Image):
return image.resize(self.size, Image.BILINEAR)
else:
raise Exception('unsupported type')
class EnhancedCompose(object):
"""Composes several transforms together.
Args:
transforms (List[Transform]): list of transforms to compose.
Example:
>>> transforms.Compose([
>>> transforms.CenterCrop(10),
>>> transforms.ToTensor(),
>>> ])
"""
def __init__(self, transforms):
self.transforms = transforms
def __call__(self, img):
for t in self.transforms:
if isinstance(t, collections.Sequence):
assert isinstance(img, collections.Sequence) and len(img) == len(
t), "size of image group and transform group does not fit"
tmp_ = []
for i, im_ in enumerate(img):
if callable(t[i]):
tmp_.append(t[i](im_))
else:
tmp_.append(im_)
img = tmp_
elif callable(t):
img = t(img)
elif t is None:
continue
else:
raise Exception('unexpected type')
return img
