mmtrack.models.track_heads.roi_track_head 源代码
# Copyright (c) OpenMMLab. All rights reserved.
from abc import ABCMeta
from mmcv.runner import BaseModule
from mmdet.core import bbox2roi, build_assigner, build_sampler
from mmdet.models import HEADS, build_head, build_roi_extractor
[文档]@HEADS.register_module()
class RoITrackHead(BaseModule, metaclass=ABCMeta):
"""The roi track head.
This module is used in multi-object tracking methods, such as MaskTrack
R-CNN.
Args:
roi_extractor (dict): Configuration of roi extractor. Defaults to None.
embed_head (dict): Configuration of embed head. Defaults to None.
train_cfg (dict): Configuration when training. Defaults to None.
test_cfg (dict): Configuration when testing. Defaults to None.
init_cfg (dict): Configuration of initialization. Defaults to None.
"""
def __init__(self,
roi_extractor=None,
embed_head=None,
regress_head=None,
train_cfg=None,
test_cfg=None,
init_cfg=None,
*args,
**kwargs):
super().__init__(init_cfg=init_cfg)
self.train_cfg = train_cfg
self.test_cfg = test_cfg
if embed_head is not None:
self.init_embed_head(roi_extractor, embed_head)
if regress_head is not None:
raise NotImplementedError('Regression head is not supported yet.')
self.init_assigner_sampler()
[文档] def init_embed_head(self, roi_extractor, embed_head):
"""Initialize ``embed_head``"""
self.roi_extractor = build_roi_extractor(roi_extractor)
self.embed_head = build_head(embed_head)
[文档] def init_assigner_sampler(self):
"""Initialize assigner and sampler."""
self.bbox_assigner = None
self.bbox_sampler = None
if self.train_cfg:
self.bbox_assigner = build_assigner(self.train_cfg.assigner)
self.bbox_sampler = build_sampler(
self.train_cfg.sampler, context=self)
@property
def with_track(self):
"""bool: whether the mulit-object tracker has a embed head"""
return hasattr(self, 'embed_head') and self.embed_head is not None
[文档] def extract_roi_feats(self, x, bboxes):
"""Extract roi features."""
rois = bbox2roi(bboxes)
bbox_feats = self.roi_extractor(x[:self.roi_extractor.num_inputs],
rois)
num_bbox_per_img = [len(bbox) for bbox in bboxes]
return bbox_feats, num_bbox_per_img
[文档] def forward_train(self,
x,
ref_x,
img_metas,
proposal_list,
gt_bboxes,
ref_gt_bboxes,
gt_labels,
gt_instance_ids,
ref_gt_instance_ids,
gt_bboxes_ignore=None,
**kwargs):
"""
Args:
x (list[Tensor]): list of multi-level image features.
ref_x (list[Tensor]): list of multi-level ref_img features.
img_metas (list[dict]): list of image info dict where each dict
has: 'img_shape', 'scale_factor', 'flip', and may also contain
'filename', 'ori_shape', 'pad_shape', and 'img_norm_cfg'.
For details on the values of these keys see
`mmtrack/datasets/pipelines/formatting.py:VideoCollect`.
proposal_list (list[Tensors]): list of region proposals.
gt_bboxes (list[Tensor]): Ground truth bboxes for each image with
shape (num_gts, 4) in [tl_x, tl_y, br_x, br_y] format.
ref_gt_bboxes (list[Tensor]): Ground truth bboxes for each
reference image with shape (num_gts, 4) in
[tl_x, tl_y, br_x, br_y] format.
gt_labels (list[Tensor]): class indices corresponding to each box.
gt_instance_ids (None | list[Tensor]): specify the instance id for
each ground truth bbox.
ref_gt_instance_ids (None | list[Tensor]): specify the instance id
for each ground truth bbox of reference images.
gt_bboxes_ignore (None | list[Tensor]): specify which bounding
boxes can be ignored when computing the loss.
Returns:
dict[str, Tensor]: a dictionary of loss components
"""
# assign gts and sample proposals
if self.with_track:
num_imgs = len(img_metas)
if gt_bboxes_ignore is None:
gt_bboxes_ignore = [None for _ in range(num_imgs)]
sampling_results = []
for i in range(num_imgs):
assign_result = self.bbox_assigner.assign(
proposal_list[i], gt_bboxes[i], gt_bboxes_ignore[i],
gt_labels[i])
sampling_result = self.bbox_sampler.sample(
assign_result,
proposal_list[i],
gt_bboxes[i],
gt_labels[i],
feats=[lvl_feat[i][None] for lvl_feat in x])
sampling_results.append(sampling_result)
losses = dict()
if self.with_track:
track_results = self._track_forward_train(x, ref_x,
sampling_results,
ref_gt_bboxes,
gt_instance_ids,
ref_gt_instance_ids)
losses.update(track_results['loss_track'])
return losses
def _track_forward_train(self, x, ref_x, sampling_results, ref_gt_bboxes,
gt_instance_ids, ref_gt_instance_ids, **kwargs):
"""Run forward function and calculate loss for track head in
training."""
bboxes = [res.bboxes for res in sampling_results]
bbox_feats, num_bbox_per_img = self.extract_roi_feats(x, bboxes)
ref_bbox_feats, num_bbox_per_ref_img = self.extract_roi_feats(
ref_x, ref_gt_bboxes)
similarity_logits = self.embed_head(bbox_feats, ref_bbox_feats,
num_bbox_per_img,
num_bbox_per_ref_img)
track_targets = self.embed_head.get_targets(sampling_results,
gt_instance_ids,
ref_gt_instance_ids)
loss_track = self.embed_head.loss(similarity_logits, *track_targets)
track_results = dict(loss_track=loss_track)
return track_results
[文档] def simple_test(self, roi_feats, prev_roi_feats):
"""Test without augmentations."""
return self.embed_head(roi_feats, prev_roi_feats, [roi_feats.shape[0]],
[prev_roi_feats.shape[0]])[0]