KyanChen's picture
init
f549064
raw
history blame
No virus
2.51 kB
# Copyright (c) OpenMMLab. All rights reserved.
import numpy as np
import pycocotools.mask as mask_util
import torch
from mmengine.utils import slice_list
def split_combined_polys(polys, poly_lens, polys_per_mask):
"""Split the combined 1-D polys into masks.
A mask is represented as a list of polys, and a poly is represented as
a 1-D array. In dataset, all masks are concatenated into a single 1-D
tensor. Here we need to split the tensor into original representations.
Args:
polys (list): a list (length = image num) of 1-D tensors
poly_lens (list): a list (length = image num) of poly length
polys_per_mask (list): a list (length = image num) of poly number
of each mask
Returns:
list: a list (length = image num) of list (length = mask num) of \
list (length = poly num) of numpy array.
"""
mask_polys_list = []
for img_id in range(len(polys)):
polys_single = polys[img_id]
polys_lens_single = poly_lens[img_id].tolist()
polys_per_mask_single = polys_per_mask[img_id].tolist()
split_polys = slice_list(polys_single, polys_lens_single)
mask_polys = slice_list(split_polys, polys_per_mask_single)
mask_polys_list.append(mask_polys)
return mask_polys_list
# TODO: move this function to more proper place
def encode_mask_results(mask_results):
"""Encode bitmap mask to RLE code.
Args:
mask_results (list): bitmap mask results.
Returns:
list | tuple: RLE encoded mask.
"""
encoded_mask_results = []
for mask in mask_results:
encoded_mask_results.append(
mask_util.encode(
np.array(mask[:, :, np.newaxis], order='F',
dtype='uint8'))[0]) # encoded with RLE
return encoded_mask_results
def mask2bbox(masks):
"""Obtain tight bounding boxes of binary masks.
Args:
masks (Tensor): Binary mask of shape (n, h, w).
Returns:
Tensor: Bboxe with shape (n, 4) of \
positive region in binary mask.
"""
N = masks.shape[0]
bboxes = masks.new_zeros((N, 4), dtype=torch.float32)
x_any = torch.any(masks, dim=1)
y_any = torch.any(masks, dim=2)
for i in range(N):
x = torch.where(x_any[i, :])[0]
y = torch.where(y_any[i, :])[0]
if len(x) > 0 and len(y) > 0:
bboxes[i, :] = bboxes.new_tensor(
[x[0], y[0], x[-1] + 1, y[-1] + 1])
return bboxes