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volume_transforms.py
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volume_transforms.py
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import numpy as np
from PIL import Image
import torch
def convert_img(img):
"""Converts (H, W, C) numpy.ndarray to (C, W, H) format
"""
if len(img.shape) == 3:
img = img.transpose(2, 0, 1)
if len(img.shape) == 2:
img = np.expand_dims(img, 0)
return img
class ClipToTensor(object):
"""Convert a list of m (H x W x C) numpy.ndarrays in the range [0, 255]
to a torch.FloatTensor of shape (C x m x H x W) in the range [0, 1.0]
"""
def __init__(self, channel_nb=3, div_255=True, numpy=False):
self.channel_nb = channel_nb
self.div_255 = div_255
self.numpy = numpy
def __call__(self, clip):
"""
Args: clip (list of numpy.ndarray): clip (list of images)
to be converted to tensor.
"""
# Retrieve shape
if isinstance(clip[0], np.ndarray):
h, w, ch = clip[0].shape
assert ch == self.channel_nb, 'Got {0} instead of 3 channels'.format(
ch)
elif isinstance(clip[0], Image.Image):
w, h = clip[0].size
else:
raise TypeError('Expected numpy.ndarray or PIL.Image\
but got list of {0}'.format(type(clip[0])))
np_clip = np.zeros([self.channel_nb, len(clip), int(h), int(w)])
# Convert
for img_idx, img in enumerate(clip):
if isinstance(img, np.ndarray):
pass
elif isinstance(img, Image.Image):
img = np.array(img, copy=False)
else:
raise TypeError('Expected numpy.ndarray or PIL.Image\
but got list of {0}'.format(type(clip[0])))
img = convert_img(img)
np_clip[:, img_idx, :, :] = img
if self.numpy:
if self.div_255:
np_clip = np_clip / 255.0
return np_clip
else:
tensor_clip = torch.from_numpy(np_clip)
if not isinstance(tensor_clip, torch.FloatTensor):
tensor_clip = tensor_clip.float()
if self.div_255:
tensor_clip = torch.div(tensor_clip, 255)
return tensor_clip
# Note this norms data to -1/1
class ClipToTensor_K(object):
"""Convert a list of m (H x W x C) numpy.ndarrays in the range [0, 255]
to a torch.FloatTensor of shape (C x m x H x W) in the range [0, 1.0]
"""
def __init__(self, channel_nb=3, div_255=True, numpy=False):
self.channel_nb = channel_nb
self.div_255 = div_255
self.numpy = numpy
def __call__(self, clip):
"""
Args: clip (list of numpy.ndarray): clip (list of images)
to be converted to tensor.
"""
# Retrieve shape
if isinstance(clip[0], np.ndarray):
h, w, ch = clip[0].shape
assert ch == self.channel_nb, 'Got {0} instead of 3 channels'.format(
ch)
elif isinstance(clip[0], Image.Image):
w, h = clip[0].size
else:
raise TypeError('Expected numpy.ndarray or PIL.Image\
but got list of {0}'.format(type(clip[0])))
np_clip = np.zeros([self.channel_nb, len(clip), int(h), int(w)])
# Convert
for img_idx, img in enumerate(clip):
if isinstance(img, np.ndarray):
pass
elif isinstance(img, Image.Image):
img = np.array(img, copy=False)
else:
raise TypeError('Expected numpy.ndarray or PIL.Image\
but got list of {0}'.format(type(clip[0])))
img = convert_img(img)
np_clip[:, img_idx, :, :] = img
if self.numpy:
if self.div_255:
np_clip = (np_clip - 127.5) / 127.5
return np_clip
else:
tensor_clip = torch.from_numpy(np_clip)
if not isinstance(tensor_clip, torch.FloatTensor):
tensor_clip = tensor_clip.float()
if self.div_255:
tensor_clip = torch.div(torch.sub(tensor_clip, 127.5), 127.5)
return tensor_clip
class ToTensor(object):
"""Converts numpy array to tensor
"""
def __call__(self, array):
tensor = torch.from_numpy(array)
return tensor