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# Copyright (c) OpenMMLab. All rights reserved.
from typing import List, Optional, Tuple, Union
import numpy as np
import torch
import torch.nn as nn
from mmcv.cnn import ConvModule
from mmengine.config import ConfigDict
from mmengine.structures import InstanceData
from torch import Tensor
from mmdet.registry import MODELS, TASK_UTILS
from mmdet.utils import (ConfigType, InstanceList, MultiConfig, OptConfigType,
OptInstanceList)
from ..task_modules.samplers import PseudoSampler
from ..utils import (filter_scores_and_topk, images_to_levels, multi_apply,
unmap)
from .base_dense_head import BaseDenseHead
from .guided_anchor_head import GuidedAnchorHead
@MODELS.register_module()
class SABLRetinaHead(BaseDenseHead):
"""Side-Aware Boundary Localization (SABL) for RetinaNet.
The anchor generation, assigning and sampling in SABLRetinaHead
are the same as GuidedAnchorHead for guided anchoring.
Please refer to https://arxiv.org/abs/1912.04260 for more details.
Args:
num_classes (int): Number of classes.
in_channels (int): Number of channels in the input feature map.
stacked_convs (int): Number of Convs for classification and
regression branches. Defaults to 4.
feat_channels (int): Number of hidden channels. Defaults to 256.
approx_anchor_generator (:obj:`ConfigType` or dict): Config dict for
approx generator.
square_anchor_generator (:obj:`ConfigDict` or dict): Config dict for
square generator.
conv_cfg (:obj:`ConfigDict` or dict, optional): Config dict for
ConvModule. Defaults to None.
norm_cfg (:obj:`ConfigDict` or dict, optional): Config dict for
Norm Layer. Defaults to None.
bbox_coder (:obj:`ConfigDict` or dict): Config dict for bbox coder.
reg_decoded_bbox (bool): If true, the regression loss would be
applied directly on decoded bounding boxes, converting both
the predicted boxes and regression targets to absolute
coordinates format. Default False. It should be ``True`` when
using ``IoULoss``, ``GIoULoss``, or ``DIoULoss`` in the bbox head.
train_cfg (:obj:`ConfigDict` or dict, optional): Training config of
SABLRetinaHead.
test_cfg (:obj:`ConfigDict` or dict, optional): Testing config of
SABLRetinaHead.
loss_cls (:obj:`ConfigDict` or dict): Config of classification loss.
loss_bbox_cls (:obj:`ConfigDict` or dict): Config of classification
loss for bbox branch.
loss_bbox_reg (:obj:`ConfigDict` or dict): Config of regression loss
for bbox branch.
init_cfg (:obj:`ConfigDict` or dict or list[:obj:`ConfigDict` or \
dict], optional): Initialization config dict.
"""
def __init__(
self,
num_classes: int,
in_channels: int,
stacked_convs: int = 4,
feat_channels: int = 256,
approx_anchor_generator: ConfigType = dict(
type='AnchorGenerator',
octave_base_scale=4,
scales_per_octave=3,
ratios=[0.5, 1.0, 2.0],
strides=[8, 16, 32, 64, 128]),
square_anchor_generator: ConfigType = dict(
type='AnchorGenerator',
ratios=[1.0],
scales=[4],
strides=[8, 16, 32, 64, 128]),
conv_cfg: OptConfigType = None,
norm_cfg: OptConfigType = None,
bbox_coder: ConfigType = dict(
type='BucketingBBoxCoder', num_buckets=14, scale_factor=3.0),
reg_decoded_bbox: bool = False,
train_cfg: OptConfigType = None,
test_cfg: OptConfigType = None,
loss_cls: ConfigType = dict(
type='FocalLoss',
use_sigmoid=True,
gamma=2.0,
alpha=0.25,
loss_weight=1.0),
loss_bbox_cls: ConfigType = dict(
type='CrossEntropyLoss', use_sigmoid=True, loss_weight=1.5),
loss_bbox_reg: ConfigType = dict(
type='SmoothL1Loss', beta=1.0 / 9.0, loss_weight=1.5),
init_cfg: MultiConfig = dict(
type='Normal',
layer='Conv2d',
std=0.01,
override=dict(
type='Normal', name='retina_cls', std=0.01, bias_prob=0.01))
) -> None:
super().__init__(init_cfg=init_cfg)
self.in_channels = in_channels
self.num_classes = num_classes
self.feat_channels = feat_channels
self.num_buckets = bbox_coder['num_buckets']
self.side_num = int(np.ceil(self.num_buckets / 2))
assert (approx_anchor_generator['octave_base_scale'] ==
square_anchor_generator['scales'][0])
assert (approx_anchor_generator['strides'] ==
square_anchor_generator['strides'])
self.approx_anchor_generator = TASK_UTILS.build(
approx_anchor_generator)
self.square_anchor_generator = TASK_UTILS.build(
square_anchor_generator)
self.approxs_per_octave = (
self.approx_anchor_generator.num_base_priors[0])
# one anchor per location
self.num_base_priors = self.square_anchor_generator.num_base_priors[0]
self.stacked_convs = stacked_convs
self.conv_cfg = conv_cfg
self.norm_cfg = norm_cfg
self.reg_decoded_bbox = reg_decoded_bbox
self.use_sigmoid_cls = loss_cls.get('use_sigmoid', False)
if self.use_sigmoid_cls:
self.cls_out_channels = num_classes
else:
self.cls_out_channels = num_classes + 1
self.bbox_coder = TASK_UTILS.build(bbox_coder)
self.loss_cls = MODELS.build(loss_cls)
self.loss_bbox_cls = MODELS.build(loss_bbox_cls)
self.loss_bbox_reg = MODELS.build(loss_bbox_reg)
self.train_cfg = train_cfg
self.test_cfg = test_cfg
if self.train_cfg:
self.assigner = TASK_UTILS.build(self.train_cfg['assigner'])
# use PseudoSampler when sampling is False
if 'sampler' in self.train_cfg:
self.sampler = TASK_UTILS.build(
self.train_cfg['sampler'], default_args=dict(context=self))
else:
self.sampler = PseudoSampler(context=self)
self._init_layers()
def _init_layers(self) -> None:
self.relu = nn.ReLU(inplace=True)
self.cls_convs = nn.ModuleList()
self.reg_convs = nn.ModuleList()
for i in range(self.stacked_convs):
chn = self.in_channels if i == 0 else self.feat_channels
self.cls_convs.append(
ConvModule(
chn,
self.feat_channels,
3,
stride=1,
padding=1,
conv_cfg=self.conv_cfg,
norm_cfg=self.norm_cfg))
self.reg_convs.append(
ConvModule(
chn,
self.feat_channels,
3,
stride=1,
padding=1,
conv_cfg=self.conv_cfg,
norm_cfg=self.norm_cfg))
self.retina_cls = nn.Conv2d(
self.feat_channels, self.cls_out_channels, 3, padding=1)
self.retina_bbox_reg = nn.Conv2d(
self.feat_channels, self.side_num * 4, 3, padding=1)
self.retina_bbox_cls = nn.Conv2d(
self.feat_channels, self.side_num * 4, 3, padding=1)
def forward_single(self, x: Tensor) -> Tuple[Tensor, Tensor]:
cls_feat = x
reg_feat = x
for cls_conv in self.cls_convs:
cls_feat = cls_conv(cls_feat)
for reg_conv in self.reg_convs:
reg_feat = reg_conv(reg_feat)
cls_score = self.retina_cls(cls_feat)
bbox_cls_pred = self.retina_bbox_cls(reg_feat)
bbox_reg_pred = self.retina_bbox_reg(reg_feat)
bbox_pred = (bbox_cls_pred, bbox_reg_pred)
return cls_score, bbox_pred
def forward(self, feats: List[Tensor]) -> Tuple[List[Tensor]]:
return multi_apply(self.forward_single, feats)
def get_anchors(
self,
featmap_sizes: List[tuple],
img_metas: List[dict],
device: Union[torch.device, str] = 'cuda'
) -> Tuple[List[List[Tensor]], List[List[Tensor]]]:
"""Get squares according to feature map sizes and guided anchors.
Args:
featmap_sizes (list[tuple]): Multi-level feature map sizes.
img_metas (list[dict]): Image meta info.
device (torch.device | str): device for returned tensors
Returns:
tuple: square approxs of each image
"""
num_imgs = len(img_metas)
# since feature map sizes of all images are the same, we only compute
# squares for one time
multi_level_squares = self.square_anchor_generator.grid_priors(
featmap_sizes, device=device)
squares_list = [multi_level_squares for _ in range(num_imgs)]
return squares_list
def get_targets(self,
approx_list: List[List[Tensor]],
inside_flag_list: List[List[Tensor]],
square_list: List[List[Tensor]],
batch_gt_instances: InstanceList,
batch_img_metas,
batch_gt_instances_ignore: OptInstanceList = None,
unmap_outputs=True) -> tuple:
"""Compute bucketing targets.
Args:
approx_list (list[list[Tensor]]): Multi level approxs of each
image.
inside_flag_list (list[list[Tensor]]): Multi level inside flags of
each image.
square_list (list[list[Tensor]]): Multi level squares of each
image.
batch_gt_instances (list[:obj:`InstanceData`]): Batch of
gt_instance. It usually includes ``bboxes`` and ``labels``
attributes.
batch_img_metas (list[dict]): Meta information of each image, e.g.,
image size, scaling factor, etc.
batch_gt_instances_ignore (list[:obj:`InstanceData`], optional):
Batch of gt_instances_ignore. It includes ``bboxes`` attribute
data that is ignored during training and testing.
Defaults to None.
unmap_outputs (bool): Whether to map outputs back to the original
set of anchors. Defaults to True.
Returns:
tuple: Returns a tuple containing learning targets.
- labels_list (list[Tensor]): Labels of each level.
- label_weights_list (list[Tensor]): Label weights of each level.
- bbox_cls_targets_list (list[Tensor]): BBox cls targets of \
each level.
- bbox_cls_weights_list (list[Tensor]): BBox cls weights of \
each level.
- bbox_reg_targets_list (list[Tensor]): BBox reg targets of \
each level.
- bbox_reg_weights_list (list[Tensor]): BBox reg weights of \
each level.
- num_total_pos (int): Number of positive samples in all images.
- num_total_neg (int): Number of negative samples in all images.
"""
num_imgs = len(batch_img_metas)
assert len(approx_list) == len(inside_flag_list) == len(
square_list) == num_imgs
# anchor number of multi levels
num_level_squares = [squares.size(0) for squares in square_list[0]]
# concat all level anchors and flags to a single tensor
inside_flag_flat_list = []
approx_flat_list = []
square_flat_list = []
for i in range(num_imgs):
assert len(square_list[i]) == len(inside_flag_list[i])
inside_flag_flat_list.append(torch.cat(inside_flag_list[i]))
approx_flat_list.append(torch.cat(approx_list[i]))
square_flat_list.append(torch.cat(square_list[i]))
# compute targets for each image
if batch_gt_instances_ignore is None:
batch_gt_instances_ignore = [None for _ in range(num_imgs)]
(all_labels, all_label_weights, all_bbox_cls_targets,
all_bbox_cls_weights, all_bbox_reg_targets, all_bbox_reg_weights,
pos_inds_list, neg_inds_list, sampling_results_list) = multi_apply(
self._get_targets_single,
approx_flat_list,
inside_flag_flat_list,
square_flat_list,
batch_gt_instances,
batch_img_metas,
batch_gt_instances_ignore,
unmap_outputs=unmap_outputs)
# sampled anchors of all images
avg_factor = sum(
[results.avg_factor for results in sampling_results_list])
# split targets to a list w.r.t. multiple levels
labels_list = images_to_levels(all_labels, num_level_squares)
label_weights_list = images_to_levels(all_label_weights,
num_level_squares)
bbox_cls_targets_list = images_to_levels(all_bbox_cls_targets,
num_level_squares)
bbox_cls_weights_list = images_to_levels(all_bbox_cls_weights,
num_level_squares)
bbox_reg_targets_list = images_to_levels(all_bbox_reg_targets,
num_level_squares)
bbox_reg_weights_list = images_to_levels(all_bbox_reg_weights,
num_level_squares)
return (labels_list, label_weights_list, bbox_cls_targets_list,
bbox_cls_weights_list, bbox_reg_targets_list,
bbox_reg_weights_list, avg_factor)
def _get_targets_single(self,
flat_approxs: Tensor,
inside_flags: Tensor,
flat_squares: Tensor,
gt_instances: InstanceData,
img_meta: dict,
gt_instances_ignore: Optional[InstanceData] = None,
unmap_outputs: bool = True) -> tuple:
"""Compute regression and classification targets for anchors in a
single image.
Args:
flat_approxs (Tensor): flat approxs of a single image,
shape (n, 4)
inside_flags (Tensor): inside flags of a single image,
shape (n, ).
flat_squares (Tensor): flat squares of a single image,
shape (approxs_per_octave * n, 4)
gt_instances (:obj:`InstanceData`): Ground truth of instance
annotations. It should includes ``bboxes`` and ``labels``
attributes.
img_meta (dict): Meta information for current image.
gt_instances_ignore (:obj:`InstanceData`, optional): Instances
to be ignored during training. It includes ``bboxes`` attribute
data that is ignored during training and testing.
Defaults to None.
unmap_outputs (bool): Whether to map outputs back to the original
set of anchors. Defaults to True.
Returns:
tuple:
- labels_list (Tensor): Labels in a single image.
- label_weights (Tensor): Label weights in a single image.
- bbox_cls_targets (Tensor): BBox cls targets in a single image.
- bbox_cls_weights (Tensor): BBox cls weights in a single image.
- bbox_reg_targets (Tensor): BBox reg targets in a single image.
- bbox_reg_weights (Tensor): BBox reg weights in a single image.
- num_total_pos (int): Number of positive samples in a single \
image.
- num_total_neg (int): Number of negative samples in a single \
image.
- sampling_result (:obj:`SamplingResult`): Sampling result object.
"""
if not inside_flags.any():
raise ValueError(
'There is no valid anchor inside the image boundary. Please '
'check the image size and anchor sizes, or set '
'``allowed_border`` to -1 to skip the condition.')
# assign gt and sample anchors
num_square = flat_squares.size(0)
approxs = flat_approxs.view(num_square, self.approxs_per_octave, 4)
approxs = approxs[inside_flags, ...]
squares = flat_squares[inside_flags, :]
pred_instances = InstanceData()
pred_instances.priors = squares
pred_instances.approxs = approxs
assign_result = self.assigner.assign(pred_instances, gt_instances,
gt_instances_ignore)
sampling_result = self.sampler.sample(assign_result, pred_instances,
gt_instances)
num_valid_squares = squares.shape[0]
bbox_cls_targets = squares.new_zeros(
(num_valid_squares, self.side_num * 4))
bbox_cls_weights = squares.new_zeros(
(num_valid_squares, self.side_num * 4))
bbox_reg_targets = squares.new_zeros(
(num_valid_squares, self.side_num * 4))
bbox_reg_weights = squares.new_zeros(
(num_valid_squares, self.side_num * 4))
labels = squares.new_full((num_valid_squares, ),
self.num_classes,
dtype=torch.long)
label_weights = squares.new_zeros(num_valid_squares, dtype=torch.float)
pos_inds = sampling_result.pos_inds
neg_inds = sampling_result.neg_inds
if len(pos_inds) > 0:
(pos_bbox_reg_targets, pos_bbox_reg_weights, pos_bbox_cls_targets,
pos_bbox_cls_weights) = self.bbox_coder.encode(
sampling_result.pos_bboxes, sampling_result.pos_gt_bboxes)
bbox_cls_targets[pos_inds, :] = pos_bbox_cls_targets
bbox_reg_targets[pos_inds, :] = pos_bbox_reg_targets
bbox_cls_weights[pos_inds, :] = pos_bbox_cls_weights
bbox_reg_weights[pos_inds, :] = pos_bbox_reg_weights
labels[pos_inds] = sampling_result.pos_gt_labels
if self.train_cfg['pos_weight'] <= 0:
label_weights[pos_inds] = 1.0
else:
label_weights[pos_inds] = self.train_cfg['pos_weight']
if len(neg_inds) > 0:
label_weights[neg_inds] = 1.0
# map up to original set of anchors
if unmap_outputs:
num_total_anchors = flat_squares.size(0)
labels = unmap(
labels, num_total_anchors, inside_flags, fill=self.num_classes)
label_weights = unmap(label_weights, num_total_anchors,
inside_flags)
bbox_cls_targets = unmap(bbox_cls_targets, num_total_anchors,
inside_flags)
bbox_cls_weights = unmap(bbox_cls_weights, num_total_anchors,
inside_flags)
bbox_reg_targets = unmap(bbox_reg_targets, num_total_anchors,
inside_flags)
bbox_reg_weights = unmap(bbox_reg_weights, num_total_anchors,
inside_flags)
return (labels, label_weights, bbox_cls_targets, bbox_cls_weights,
bbox_reg_targets, bbox_reg_weights, pos_inds, neg_inds,
sampling_result)
def loss_by_feat_single(self, cls_score: Tensor, bbox_pred: Tensor,
labels: Tensor, label_weights: Tensor,
bbox_cls_targets: Tensor, bbox_cls_weights: Tensor,
bbox_reg_targets: Tensor, bbox_reg_weights: Tensor,
avg_factor: float) -> Tuple[Tensor]:
"""Calculate the loss of a single scale level based on the features
extracted by the detection head.
Args:
cls_score (Tensor): Box scores for each scale level
Has shape (N, num_anchors * num_classes, H, W).
bbox_pred (Tensor): Box energies / deltas for each scale
level with shape (N, num_anchors * 4, H, W).
labels (Tensor): Labels in a single image.
label_weights (Tensor): Label weights in a single level.
bbox_cls_targets (Tensor): BBox cls targets in a single level.
bbox_cls_weights (Tensor): BBox cls weights in a single level.
bbox_reg_targets (Tensor): BBox reg targets in a single level.
bbox_reg_weights (Tensor): BBox reg weights in a single level.
avg_factor (int): Average factor that is used to average the loss.
Returns:
tuple: loss components.
"""
# classification loss
labels = labels.reshape(-1)
label_weights = label_weights.reshape(-1)
cls_score = cls_score.permute(0, 2, 3,
1).reshape(-1, self.cls_out_channels)
loss_cls = self.loss_cls(
cls_score, labels, label_weights, avg_factor=avg_factor)
# regression loss
bbox_cls_targets = bbox_cls_targets.reshape(-1, self.side_num * 4)
bbox_cls_weights = bbox_cls_weights.reshape(-1, self.side_num * 4)
bbox_reg_targets = bbox_reg_targets.reshape(-1, self.side_num * 4)
bbox_reg_weights = bbox_reg_weights.reshape(-1, self.side_num * 4)
(bbox_cls_pred, bbox_reg_pred) = bbox_pred
bbox_cls_pred = bbox_cls_pred.permute(0, 2, 3, 1).reshape(
-1, self.side_num * 4)
bbox_reg_pred = bbox_reg_pred.permute(0, 2, 3, 1).reshape(
-1, self.side_num * 4)
loss_bbox_cls = self.loss_bbox_cls(
bbox_cls_pred,
bbox_cls_targets.long(),
bbox_cls_weights,
avg_factor=avg_factor * 4 * self.side_num)
loss_bbox_reg = self.loss_bbox_reg(
bbox_reg_pred,
bbox_reg_targets,
bbox_reg_weights,
avg_factor=avg_factor * 4 * self.bbox_coder.offset_topk)
return loss_cls, loss_bbox_cls, loss_bbox_reg
def loss_by_feat(
self,
cls_scores: List[Tensor],
bbox_preds: List[Tensor],
batch_gt_instances: InstanceList,
batch_img_metas: List[dict],
batch_gt_instances_ignore: OptInstanceList = None) -> dict:
"""Calculate the loss based on the features extracted by the detection
head.
Args:
cls_scores (list[Tensor]): Box scores for each scale level
has shape (N, num_anchors * num_classes, H, W).
bbox_preds (list[Tensor]): Box energies / deltas for each scale
level with shape (N, num_anchors * 4, H, W).
batch_gt_instances (list[:obj:`InstanceData`]): Batch of
gt_instance. It usually includes ``bboxes`` and ``labels``
attributes.
batch_img_metas (list[dict]): Meta information of each image, e.g.,
image size, scaling factor, etc.
batch_gt_instances_ignore (list[:obj:`InstanceData`], optional):
Batch of gt_instances_ignore. It includes ``bboxes`` attribute
data that is ignored during training and testing.
Defaults to None.
Returns:
dict: A dictionary of loss components.
"""
featmap_sizes = [featmap.size()[-2:] for featmap in cls_scores]
assert len(featmap_sizes) == self.approx_anchor_generator.num_levels
device = cls_scores[0].device
# get sampled approxes
approxs_list, inside_flag_list = GuidedAnchorHead.get_sampled_approxs(
self, featmap_sizes, batch_img_metas, device=device)
square_list = self.get_anchors(
featmap_sizes, batch_img_metas, device=device)
cls_reg_targets = self.get_targets(
approxs_list,
inside_flag_list,
square_list,
batch_gt_instances,
batch_img_metas,
batch_gt_instances_ignore=batch_gt_instances_ignore)
(labels_list, label_weights_list, bbox_cls_targets_list,
bbox_cls_weights_list, bbox_reg_targets_list, bbox_reg_weights_list,
avg_factor) = cls_reg_targets
losses_cls, losses_bbox_cls, losses_bbox_reg = multi_apply(
self.loss_by_feat_single,
cls_scores,
bbox_preds,
labels_list,
label_weights_list,
bbox_cls_targets_list,
bbox_cls_weights_list,
bbox_reg_targets_list,
bbox_reg_weights_list,
avg_factor=avg_factor)
return dict(
loss_cls=losses_cls,
loss_bbox_cls=losses_bbox_cls,
loss_bbox_reg=losses_bbox_reg)
def predict_by_feat(self,
cls_scores: List[Tensor],
bbox_preds: List[Tensor],
batch_img_metas: List[dict],
cfg: Optional[ConfigDict] = None,
rescale: bool = False,
with_nms: bool = True) -> InstanceList:
"""Transform a batch of output features extracted from the head into
bbox results.
Note: When score_factors is not None, the cls_scores are
usually multiplied by it then obtain the real score used in NMS,
such as CenterNess in FCOS, IoU branch in ATSS.
Args:
cls_scores (list[Tensor]): Classification scores for all
scale levels, each is a 4D-tensor, has shape
(batch_size, num_priors * num_classes, H, W).
bbox_preds (list[Tensor]): Box energies / deltas for all
scale levels, each is a 4D-tensor, has shape
(batch_size, num_priors * 4, H, W).
batch_img_metas (list[dict], Optional): Batch image meta info.
cfg (:obj:`ConfigDict`, optional): Test / postprocessing
configuration, if None, test_cfg would be used.
Defaults to None.
rescale (bool): If True, return boxes in original image space.
Defaults to False.
with_nms (bool): If True, do nms before return boxes.
Defaults to True.
Returns:
list[:obj:`InstanceData`]: Object detection results of each image
after the post process. Each item usually contains following keys.
- scores (Tensor): Classification scores, has a shape
(num_instance, )
- labels (Tensor): Labels of bboxes, has a shape
(num_instances, ).
- bboxes (Tensor): Has a shape (num_instances, 4),
the last dimension 4 arrange as (x1, y1, x2, y2).
"""
assert len(cls_scores) == len(bbox_preds)
num_levels = len(cls_scores)
featmap_sizes = [featmap.size()[-2:] for featmap in cls_scores]
device = cls_scores[0].device
mlvl_anchors = self.get_anchors(
featmap_sizes, batch_img_metas, device=device)
result_list = []
for img_id in range(len(batch_img_metas)):
cls_score_list = [
cls_scores[i][img_id].detach() for i in range(num_levels)
]
bbox_cls_pred_list = [
bbox_preds[i][0][img_id].detach() for i in range(num_levels)
]
bbox_reg_pred_list = [
bbox_preds[i][1][img_id].detach() for i in range(num_levels)
]
proposals = self._predict_by_feat_single(
cls_scores=cls_score_list,
bbox_cls_preds=bbox_cls_pred_list,
bbox_reg_preds=bbox_reg_pred_list,
mlvl_anchors=mlvl_anchors[img_id],
img_meta=batch_img_metas[img_id],
cfg=cfg,
rescale=rescale,
with_nms=with_nms)
result_list.append(proposals)
return result_list
def _predict_by_feat_single(self,
cls_scores: List[Tensor],
bbox_cls_preds: List[Tensor],
bbox_reg_preds: List[Tensor],
mlvl_anchors: List[Tensor],
img_meta: dict,
cfg: ConfigDict,
rescale: bool = False,
with_nms: bool = True) -> InstanceData:
cfg = self.test_cfg if cfg is None else cfg
nms_pre = cfg.get('nms_pre', -1)
mlvl_bboxes = []
mlvl_scores = []
mlvl_confids = []
mlvl_labels = []
assert len(cls_scores) == len(bbox_cls_preds) == len(
bbox_reg_preds) == len(mlvl_anchors)
for cls_score, bbox_cls_pred, bbox_reg_pred, anchors in zip(
cls_scores, bbox_cls_preds, bbox_reg_preds, mlvl_anchors):
assert cls_score.size()[-2:] == bbox_cls_pred.size(
)[-2:] == bbox_reg_pred.size()[-2::]
cls_score = cls_score.permute(1, 2,
0).reshape(-1, self.cls_out_channels)
if self.use_sigmoid_cls:
scores = cls_score.sigmoid()
else:
scores = cls_score.softmax(-1)[:, :-1]
bbox_cls_pred = bbox_cls_pred.permute(1, 2, 0).reshape(
-1, self.side_num * 4)
bbox_reg_pred = bbox_reg_pred.permute(1, 2, 0).reshape(
-1, self.side_num * 4)
# After https://github.com/open-mmlab/mmdetection/pull/6268/,
# this operation keeps fewer bboxes under the same `nms_pre`.
# There is no difference in performance for most models. If you
# find a slight drop in performance, you can set a larger
# `nms_pre` than before.
results = filter_scores_and_topk(
scores, cfg.score_thr, nms_pre,
dict(
anchors=anchors,
bbox_cls_pred=bbox_cls_pred,
bbox_reg_pred=bbox_reg_pred))
scores, labels, _, filtered_results = results
anchors = filtered_results['anchors']
bbox_cls_pred = filtered_results['bbox_cls_pred']
bbox_reg_pred = filtered_results['bbox_reg_pred']
bbox_preds = [
bbox_cls_pred.contiguous(),
bbox_reg_pred.contiguous()
]
bboxes, confids = self.bbox_coder.decode(
anchors.contiguous(),
bbox_preds,
max_shape=img_meta['img_shape'])
mlvl_bboxes.append(bboxes)
mlvl_scores.append(scores)
mlvl_confids.append(confids)
mlvl_labels.append(labels)
results = InstanceData()
results.bboxes = torch.cat(mlvl_bboxes)
results.scores = torch.cat(mlvl_scores)
results.score_factors = torch.cat(mlvl_confids)
results.labels = torch.cat(mlvl_labels)
return self._bbox_post_process(
results=results,
cfg=cfg,
rescale=rescale,
with_nms=with_nms,
img_meta=img_meta)