from functools import partial
import mmcv
import numpy as np
import torch
from six.moves import map, zip
def tensor2imgs(tensor, mean=(0, 0, 0), std=(1, 1, 1), to_rgb=True):
"""Convert tensor to images.
Args:
tensor (torch.Tensor): Tensor that contains multiple images
mean (tuple[float], optional): Mean of images. Defaults to (0, 0, 0).
std (tuple[float], optional): Standard deviation of images.
Defaults to (1, 1, 1).
to_rgb (bool, optional): Whether convert the images to RGB format.
Defaults to True.
Returns:
list[np.ndarray]: A list that contains multiple images.
"""
num_imgs = tensor.size(0)
mean = np.array(mean, dtype=np.float32)
std = np.array(std, dtype=np.float32)
imgs = []
for img_id in range(num_imgs):
img = tensor[img_id, ...].cpu().numpy().transpose(1, 2, 0)
img = mmcv.imdenormalize(
img, mean, std, to_bgr=to_rgb).astype(np.uint8)
imgs.append(np.ascontiguousarray(img))
return imgs
def multi_apply(func, *args, **kwargs):
"""Apply function to a list of arguments.
Note:
This function applies the ``func`` to multiple inputs and
map the multiple outputs of the ``func`` into different
list. Each list contains the same type of outputs corresponding
to different inputs.
Args:
func (Function): A function that will be applied to a list of
arguments
Returns:
tuple(list): A tuple containing multiple list, each list contains
a kind of returned results by the function
"""
pfunc = partial(func, **kwargs) if kwargs else func
map_results = map(pfunc, *args)
return tuple(map(list, zip(*map_results)))
def unmap(data, count, inds, fill=0):
"""Unmap a subset of item (data) back to the original set of items (of size
count)"""
if data.dim() == 1:
ret = data.new_full((count, ), fill)
ret[inds.type(torch.bool)] = data
else:
new_size = (count, ) + data.size()[1:]
ret = data.new_full(new_size, fill)
ret[inds.type(torch.bool), :] = data
return ret
