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# Copyright (c) OpenMMLab. All rights reserved.
import numpy as np
import torch
from torch.nn.modules.utils import _pair
def mask_target(pos_proposals_list, pos_assigned_gt_inds_list, gt_masks_list,
cfg):
"""Compute mask target for positive proposals in multiple images.
Args:
pos_proposals_list (list[Tensor]): Positive proposals in multiple
images, each has shape (num_pos, 4).
pos_assigned_gt_inds_list (list[Tensor]): Assigned GT indices for each
positive proposals, each has shape (num_pos,).
gt_masks_list (list[:obj:`BaseInstanceMasks`]): Ground truth masks of
each image.
cfg (dict): Config dict that specifies the mask size.
Returns:
Tensor: Mask target of each image, has shape (num_pos, w, h).
Example:
>>> from mmengine.config import Config
>>> import mmdet
>>> from mmdet.data_elements.mask import BitmapMasks
>>> from mmdet.data_elements.mask.mask_target import *
>>> H, W = 17, 18
>>> cfg = Config({'mask_size': (13, 14)})
>>> rng = np.random.RandomState(0)
>>> # Positive proposals (tl_x, tl_y, br_x, br_y) for each image
>>> pos_proposals_list = [
>>> torch.Tensor([
>>> [ 7.2425, 5.5929, 13.9414, 14.9541],
>>> [ 7.3241, 3.6170, 16.3850, 15.3102],
>>> ]),
>>> torch.Tensor([
>>> [ 4.8448, 6.4010, 7.0314, 9.7681],
>>> [ 5.9790, 2.6989, 7.4416, 4.8580],
>>> [ 0.0000, 0.0000, 0.1398, 9.8232],
>>> ]),
>>> ]
>>> # Corresponding class index for each proposal for each image
>>> pos_assigned_gt_inds_list = [
>>> torch.LongTensor([7, 0]),
>>> torch.LongTensor([5, 4, 1]),
>>> ]
>>> # Ground truth mask for each true object for each image
>>> gt_masks_list = [
>>> BitmapMasks(rng.rand(8, H, W), height=H, width=W),
>>> BitmapMasks(rng.rand(6, H, W), height=H, width=W),
>>> ]
>>> mask_targets = mask_target(
>>> pos_proposals_list, pos_assigned_gt_inds_list,
>>> gt_masks_list, cfg)
>>> assert mask_targets.shape == (5,) + cfg['mask_size']
"""
cfg_list = [cfg for _ in range(len(pos_proposals_list))]
mask_targets = map(mask_target_single, pos_proposals_list,
pos_assigned_gt_inds_list, gt_masks_list, cfg_list)
mask_targets = list(mask_targets)
if len(mask_targets) > 0:
mask_targets = torch.cat(mask_targets)
return mask_targets
def mask_target_single(pos_proposals, pos_assigned_gt_inds, gt_masks, cfg):
"""Compute mask target for each positive proposal in the image.
Args:
pos_proposals (Tensor): Positive proposals.
pos_assigned_gt_inds (Tensor): Assigned GT inds of positive proposals.
gt_masks (:obj:`BaseInstanceMasks`): GT masks in the format of Bitmap
or Polygon.
cfg (dict): Config dict that indicate the mask size.
Returns:
Tensor: Mask target of each positive proposals in the image.
Example:
>>> from mmengine.config import Config
>>> import mmdet
>>> from mmdet.data_elements.mask import BitmapMasks
>>> from mmdet.data_elements.mask.mask_target import * # NOQA
>>> H, W = 32, 32
>>> cfg = Config({'mask_size': (7, 11)})
>>> rng = np.random.RandomState(0)
>>> # Masks for each ground truth box (relative to the image)
>>> gt_masks_data = rng.rand(3, H, W)
>>> gt_masks = BitmapMasks(gt_masks_data, height=H, width=W)
>>> # Predicted positive boxes in one image
>>> pos_proposals = torch.FloatTensor([
>>> [ 16.2, 5.5, 19.9, 20.9],
>>> [ 17.3, 13.6, 19.3, 19.3],
>>> [ 14.8, 16.4, 17.0, 23.7],
>>> [ 0.0, 0.0, 16.0, 16.0],
>>> [ 4.0, 0.0, 20.0, 16.0],
>>> ])
>>> # For each predicted proposal, its assignment to a gt mask
>>> pos_assigned_gt_inds = torch.LongTensor([0, 1, 2, 1, 1])
>>> mask_targets = mask_target_single(
>>> pos_proposals, pos_assigned_gt_inds, gt_masks, cfg)
>>> assert mask_targets.shape == (5,) + cfg['mask_size']
"""
device = pos_proposals.device
mask_size = _pair(cfg.mask_size)
binarize = not cfg.get('soft_mask_target', False)
num_pos = pos_proposals.size(0)
if num_pos > 0:
proposals_np = pos_proposals.cpu().numpy()
maxh, maxw = gt_masks.height, gt_masks.width
proposals_np[:, [0, 2]] = np.clip(proposals_np[:, [0, 2]], 0, maxw)
proposals_np[:, [1, 3]] = np.clip(proposals_np[:, [1, 3]], 0, maxh)
pos_assigned_gt_inds = pos_assigned_gt_inds.cpu().numpy()
mask_targets = gt_masks.crop_and_resize(
proposals_np,
mask_size,
device=device,
inds=pos_assigned_gt_inds,
binarize=binarize).to_ndarray()
mask_targets = torch.from_numpy(mask_targets).float().to(device)
else:
mask_targets = pos_proposals.new_zeros((0, ) + mask_size)
return mask_targets