def regress_by_class(self, rois, label, bbox_pred, img_meta):
"""Regress the bbox for the predicted class. Used in Cascade R-CNN.
Args:
rois (Tensor): shape (n, 4) or (n, 5)
label (Tensor): shape (n, )
bbox_pred (Tensor): shape (n, 4*(#class+1)) or (n, 4)
img_meta (dict): Image meta info.
Returns:
Tensor: Regressed bboxes, the same shape as input rois.
"""
assert rois.size(1) == 4 or rois.size(1) == 5, repr(rois.shape)
if not self.reg_class_agnostic:
label = label * 4
inds = torch.stack((label, label + 1, label + 2, label + 3), 1)
bbox_pred = torch.gather(bbox_pred, 1, inds)
assert bbox_pred.size(1) == 4
if rois.size(1) == 4:
new_rois = delta2bbox(rois, bbox_pred, self.target_means,
self.target_stds, img_meta['img_shape'])
else:
bboxes = delta2bbox(rois[:, 1:], bbox_pred, self.target_means,
self.target_stds, img_meta['img_shape'])
new_rois = torch.cat((rois[:, [0]], bboxes), dim=1)
return new_rois
def loss_single(self, anchors, cls_score, bbox_pred, centerness, labels,
label_weights, bbox_targets, num_total_samples, cfg):
anchors = anchors.reshape(-1, 4)
cls_score = cls_score.permute(0, 2, 3,
1).reshape(-1, self.cls_out_channels)
bbox_pred = bbox_pred.permute(0, 2, 3, 1).reshape(-1, 4)
centerness = centerness.permute(0, 2, 3, 1).reshape(-1)
bbox_targets = bbox_targets.reshape(-1, 4)
labels = labels.reshape(-1)
label_weights = label_weights.reshape(-1)
# classification loss
loss_cls = self.loss_cls(
cls_score, labels, label_weights, avg_factor=num_total_samples)
pos_inds = torch.nonzero(labels).squeeze(1)
if len(pos_inds) > 0:
pos_bbox_targets = bbox_targets[pos_inds]
pos_bbox_pred = bbox_pred[pos_inds]
pos_anchors = anchors[pos_inds]
pos_centerness = centerness[pos_inds]
centerness_targets = self.centerness_target(
pos_anchors, pos_bbox_targets)
pos_decode_bbox_pred = delta2bbox(pos_anchors, pos_bbox_pred,
self.target_means,
self.target_stds)
pos_decode_bbox_targets = delta2bbox(pos_anchors, pos_bbox_targets,
self.target_means,
self.target_stds)
# regression loss
loss_bbox = self.loss_bbox(
pos_decode_bbox_pred,
pos_decode_bbox_targets,
weight=centerness_targets,
avg_factor=1.0)
# centerness loss
loss_centerness = self.loss_centerness(
pos_centerness,
centerness_targets,
avg_factor=num_total_samples)
else:
loss_bbox = bbox_pred.sum() * 0
loss_centerness = centerness.sum() * 0
centerness_targets = torch.tensor(0).cuda()
return loss_cls, loss_bbox, loss_centerness, centerness_targets.sum()
def get_bboxes_single(self,
cls_scores,
bbox_preds,
centernesses,
mlvl_anchors,
img_shape,
scale_factor,
cfg,
rescale=False):
assert len(cls_scores) == len(bbox_preds) == len(mlvl_anchors)
mlvl_bboxes = []
mlvl_scores = []
mlvl_centerness = []
for cls_score, bbox_pred, centerness, anchors in zip(
cls_scores, bbox_preds, centernesses, mlvl_anchors):
assert cls_score.size()[-2:] == bbox_pred.size()[-2:]
scores = cls_score.permute(1, 2, 0).reshape(
-1, self.cls_out_channels).sigmoid()
bbox_pred = bbox_pred.permute(1, 2, 0).reshape(-1, 4)
centerness = centerness.permute(1, 2, 0).reshape(-1).sigmoid()
nms_pre = cfg.get('nms_pre', -1)
if nms_pre > 0 and scores.shape[0] > nms_pre:
max_scores, _ = (scores * centerness[:, None]).max(dim=1)
_, topk_inds = max_scores.topk(nms_pre)
anchors = anchors[topk_inds, :]
bbox_pred = bbox_pred[topk_inds, :]
scores = scores[topk_inds, :]
centerness = centerness[topk_inds]
bboxes = delta2bbox(anchors, bbox_pred, self.target_means,
self.target_stds, img_shape)
mlvl_bboxes.append(bboxes)
mlvl_scores.append(scores)
mlvl_centerness.append(centerness)
mlvl_bboxes = torch.cat(mlvl_bboxes)
if rescale:
mlvl_bboxes /= mlvl_bboxes.new_tensor(scale_factor)
mlvl_scores = torch.cat(mlvl_scores)
padding = mlvl_scores.new_zeros(mlvl_scores.shape[0], 1)
mlvl_scores = torch.cat([padding, mlvl_scores], dim=1)
mlvl_centerness = torch.cat(mlvl_centerness)
det_bboxes, det_labels = multiclass_nms(
mlvl_bboxes,
mlvl_scores,
cfg.score_thr,
cfg.nms,
cfg.max_per_img,
score_factors=mlvl_centerness)
return det_bboxes, det_labels
def get_bboxes_single(self,
cls_score_list,
bbox_pred_list,
mlvl_anchors,
img_shape,
scale_factor,
cfg,
rescale=False):
"""
Transform outputs for a single batch item into labeled boxes.
"""
assert len(cls_score_list) == len(bbox_pred_list) == len(mlvl_anchors)
mlvl_bboxes = []
mlvl_scores = []
for cls_score, bbox_pred, anchors in zip(cls_score_list,
bbox_pred_list, mlvl_anchors):
assert cls_score.size()[-2:] == bbox_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)
bbox_pred = bbox_pred.permute(1, 2, 0).reshape(-1, 4)
nms_pre = cfg.get('nms_pre', -1)
if nms_pre > 0 and scores.shape[0] > nms_pre:
# Get maximum scores for foreground classes.
if self.use_sigmoid_cls:
max_scores, _ = scores.max(dim=1)
else:
max_scores, _ = scores[:, 1:].max(dim=1)
_, topk_inds = max_scores.topk(nms_pre)
anchors = anchors[topk_inds, :]
bbox_pred = bbox_pred[topk_inds, :]
scores = scores[topk_inds, :]
bboxes = delta2bbox(anchors, bbox_pred, self.target_means,
self.target_stds, img_shape)
mlvl_bboxes.append(bboxes)
mlvl_scores.append(scores)
mlvl_bboxes = torch.cat(mlvl_bboxes)
if rescale:
mlvl_bboxes /= mlvl_bboxes.new_tensor(scale_factor)
mlvl_scores = torch.cat(mlvl_scores)
if self.use_sigmoid_cls:
# Add a dummy background class to the front when using sigmoid
padding = mlvl_scores.new_zeros(mlvl_scores.shape[0], 1)
mlvl_scores = torch.cat([padding, mlvl_scores], dim=1)
det_bboxes, det_labels = multiclass_nms(mlvl_bboxes, mlvl_scores,
cfg.score_thr, cfg.nms,
cfg.max_per_img)
return det_bboxes, det_labels
def get_bboxes_single(self,
cls_scores,
bbox_preds,
mlvl_anchors,
img_shape,
scale_factor,
cfg,
rescale=False):
mlvl_proposals = []
for idx in range(len(cls_scores)):
rpn_cls_score = cls_scores[idx]
rpn_bbox_pred = bbox_preds[idx]
assert rpn_cls_score.size()[-2:] == rpn_bbox_pred.size()[-2:]
rpn_cls_score = rpn_cls_score.permute(1, 2, 0)
if self.use_sigmoid_cls:
rpn_cls_score = rpn_cls_score.reshape(-1)
scores = rpn_cls_score.sigmoid()
else:
rpn_cls_score = rpn_cls_score.reshape(-1, 2)
scores = rpn_cls_score.softmax(dim=1)[:, 1]
rpn_bbox_pred = rpn_bbox_pred.permute(1, 2, 0).reshape(-1, 4)
anchors = mlvl_anchors[idx]
if cfg.nms_pre > 0 and scores.shape[0] > cfg.nms_pre:
_, topk_inds = scores.topk(cfg.nms_pre)
rpn_bbox_pred = rpn_bbox_pred[topk_inds, :]
anchors = anchors[topk_inds, :]
scores = scores[topk_inds]
proposals = delta2bbox(anchors, rpn_bbox_pred, self.target_means,
self.target_stds, img_shape)
if cfg.min_bbox_size > 0:
w = proposals[:, 2] - proposals[:, 0] + 1
h = proposals[:, 3] - proposals[:, 1] + 1
valid_inds = torch.nonzero((w >= cfg.min_bbox_size) &
(h >= cfg.min_bbox_size)).squeeze()
proposals = proposals[valid_inds, :]
scores = scores[valid_inds]
proposals = torch.cat([proposals, scores.unsqueeze(-1)], dim=-1)
proposals, _ = nms(proposals, cfg.nms_thr)
proposals = proposals[:cfg.nms_post, :]
mlvl_proposals.append(proposals)
proposals = torch.cat(mlvl_proposals, 0)
if cfg.nms_across_levels:
proposals, _ = nms(proposals, cfg.nms_thr)
proposals = proposals[:cfg.max_num, :]
else:
scores = proposals[:, 4]
num = min(cfg.max_num, proposals.shape[0])
_, topk_inds = scores.topk(num)
proposals = proposals[topk_inds, :]
return proposals
def centerness_target(self, anchors, bbox_targets):
# only calculate pos centerness targets, otherwise there may be nan
gts = delta2bbox(anchors, bbox_targets, self.target_means,
self.target_stds)
anchors_cx = (anchors[:, 2] + anchors[:, 0]) / 2
anchors_cy = (anchors[:, 3] + anchors[:, 1]) / 2
l_ = anchors_cx - gts[:, 0]
t_ = anchors_cy - gts[:, 1]
r_ = gts[:, 2] - anchors_cx
b_ = gts[:, 3] - anchors_cy
left_right = torch.stack([l_, r_], dim=1)
top_bottom = torch.stack([t_, b_], dim=1)
centerness = torch.sqrt(
(left_right.min(dim=-1)[0] / left_right.max(dim=-1)[0]) *
(top_bottom.min(dim=-1)[0] / top_bottom.max(dim=-1)[0]))
assert not torch.isnan(centerness).any()
return centerness
def get_det_bboxes(self,
rois,
cls_score,
bbox_pred,
img_shape,
scale_factor,
rescale=False,
cfg=None):
if isinstance(cls_score, list):
cls_score = sum(cls_score) / float(len(cls_score))
scores = F.softmax(cls_score, dim=1) if cls_score is not None else None
if bbox_pred is not None:
bboxes = delta2bbox(rois[:, 1:], bbox_pred, self.target_means,
self.target_stds, img_shape)
else:
bboxes = rois[:, 1:].clone()
if img_shape is not None:
bboxes[:, [0, 2]].clamp_(min=0, max=img_shape[1] - 1)
bboxes[:, [1, 3]].clamp_(min=0, max=img_shape[0] - 1)
if rescale:
if isinstance(scale_factor, float):
bboxes /= scale_factor
else:
scale_factor = torch.from_numpy(scale_factor).to(bboxes.device)
bboxes = (bboxes.view(bboxes.size(0), -1, 4) /
scale_factor).view(bboxes.size()[0], -1)
if cfg is None:
return bboxes, scores
else:
det_bboxes, det_labels = multiclass_nms(bboxes, scores,
cfg.score_thr, cfg.nms,
cfg.max_per_img)
return det_bboxes, det_labels
def loss_shape_single(self, shape_pred, bbox_anchors, bbox_gts,
anchor_weights, anchor_total_num):
shape_pred = shape_pred.permute(0, 2, 3, 1).contiguous().view(-1, 2)
bbox_anchors = bbox_anchors.contiguous().view(-1, 4)
bbox_gts = bbox_gts.contiguous().view(-1, 4)
anchor_weights = anchor_weights.contiguous().view(-1, 4)
bbox_deltas = bbox_anchors.new_full(bbox_anchors.size(), 0)
bbox_deltas[:, 2:] += shape_pred
# filter out negative samples to speed-up weighted_bounded_iou_loss
inds = torch.nonzero(anchor_weights[:, 0] > 0).squeeze(1)
bbox_deltas_ = bbox_deltas[inds]
bbox_anchors_ = bbox_anchors[inds]
bbox_gts_ = bbox_gts[inds]
anchor_weights_ = anchor_weights[inds]
pred_anchors_ = delta2bbox(bbox_anchors_,
bbox_deltas_,
self.anchoring_means,
self.anchoring_stds,
wh_ratio_clip=1e-6)
loss_shape = self.loss_shape(pred_anchors_,
bbox_gts_,
anchor_weights_,
avg_factor=anchor_total_num)
return loss_shape
def get_guided_anchors_single(self,
squares,
shape_pred,
loc_pred,
use_loc_filter=False):
"""Get guided anchors and loc masks for a single level.
Args:
square (tensor): Squares of a single level.
shape_pred (tensor): Shape predections of a single level.
loc_pred (tensor): Loc predections of a single level.
use_loc_filter (list[tensor]): Use loc filter or not.
Returns:
tuple: guided anchors, location masks
"""
# calculate location filtering mask
loc_pred = loc_pred.sigmoid().detach()
if use_loc_filter:
loc_mask = loc_pred >= self.loc_filter_thr
else:
loc_mask = loc_pred >= 0.0
mask = loc_mask.permute(1, 2, 0).expand(-1, -1, self.num_anchors)
mask = mask.contiguous().view(-1)
# calculate guided anchors
squares = squares[mask]
anchor_deltas = shape_pred.permute(1, 2, 0).contiguous().view(
-1, 2).detach()[mask]
bbox_deltas = anchor_deltas.new_full(squares.size(), 0)
bbox_deltas[:, 2:] = anchor_deltas
guided_anchors = delta2bbox(squares,
bbox_deltas,
self.anchoring_means,
self.anchoring_stds,
wh_ratio_clip=1e-6)
return guided_anchors, mask
def loss(self,
cls_scores,
bbox_preds,
gt_bboxes,
gt_labels,
img_metas,
cfg,
gt_bboxes_ignore=None):
featmap_sizes = [featmap.size()[-2:] for featmap in cls_scores]
assert len(featmap_sizes) == len(self.anchor_generators)
anchor_list, _ = self.get_anchors(featmap_sizes, img_metas)
anchors = [torch.cat(anchor) for anchor in anchor_list]
# concatenate each level
cls_scores = [
cls.permute(0, 2, 3,
1).reshape(cls.size(0), -1, self.cls_out_channels)
for cls in cls_scores
]
bbox_preds = [
bbox_pred.permute(0, 2, 3, 1).reshape(bbox_pred.size(0), -1, 4)
for bbox_pred in bbox_preds
]
cls_scores = torch.cat(cls_scores, dim=1)
bbox_preds = torch.cat(bbox_preds, dim=1)
cls_prob = torch.sigmoid(cls_scores)
box_prob = []
num_pos = 0
positive_losses = []
for _, (anchors_, gt_labels_, gt_bboxes_, cls_prob_,
bbox_preds_) in enumerate(
zip(anchors, gt_labels, gt_bboxes, cls_prob, bbox_preds)):
gt_labels_ -= 1
with torch.no_grad():
# box_localization: a_{j}^{loc}, shape: [j, 4]
pred_boxes = delta2bbox(anchors_, bbox_preds_,
self.target_means, self.target_stds)
# object_box_iou: IoU_{ij}^{loc}, shape: [i, j]
object_box_iou = bbox_overlaps(gt_bboxes_, pred_boxes)
# object_box_prob: P{a_{j} -> b_{i}}, shape: [i, j]
t1 = self.bbox_thr
t2 = object_box_iou.max(
dim=1, keepdim=True).values.clamp(min=t1 + 1e-12)
object_box_prob = ((object_box_iou - t1) / (t2 - t1)).clamp(
min=0, max=1)
# object_cls_box_prob: P{a_{j} -> b_{i}}, shape: [i, c, j]
num_obj = gt_labels_.size(0)
indices = torch.stack(
[torch.arange(num_obj).type_as(gt_labels_), gt_labels_],
dim=0)
object_cls_box_prob = torch.sparse_coo_tensor(
indices, object_box_prob)
# image_box_iou: P{a_{j} \in A_{+}}, shape: [c, j]
"""
from "start" to "end" implement:
image_box_iou = torch.sparse.max(object_cls_box_prob,
dim=0).t()
"""
# start
box_cls_prob = torch.sparse.sum(
object_cls_box_prob, dim=0).to_dense()
indices = torch.nonzero(box_cls_prob).t_()
if indices.numel() == 0:
image_box_prob = torch.zeros(
anchors_.size(0),
self.cls_out_channels).type_as(object_box_prob)
else:
nonzero_box_prob = torch.where(
(gt_labels_.unsqueeze(dim=-1) == indices[0]),
object_box_prob[:, indices[1]],
torch.tensor(
[0]).type_as(object_box_prob)).max(dim=0).values
# upmap to shape [j, c]
image_box_prob = torch.sparse_coo_tensor(
indices.flip([0]),
nonzero_box_prob,
size=(anchors_.size(0),
self.cls_out_channels)).to_dense()
# end
box_prob.append(image_box_prob)
# construct bags for objects
match_quality_matrix = bbox_overlaps(gt_bboxes_, anchors_)
_, matched = torch.topk(
match_quality_matrix,
self.pre_anchor_topk,
dim=1,
sorted=False)
del match_quality_matrix
# matched_cls_prob: P_{ij}^{cls}
matched_cls_prob = torch.gather(
cls_prob_[matched], 2,
gt_labels_.view(-1, 1, 1).repeat(1, self.pre_anchor_topk,
1)).squeeze(2)
# matched_box_prob: P_{ij}^{loc}
matched_anchors = anchors_[matched]
matched_object_targets = bbox2delta(
matched_anchors,
gt_bboxes_.unsqueeze(dim=1).expand_as(matched_anchors),
self.target_means, self.target_stds)
loss_bbox = self.loss_bbox(
bbox_preds_[matched],
matched_object_targets,
reduction_override='none').sum(-1)
matched_box_prob = torch.exp(-loss_bbox)
# positive_losses: {-log( Mean-max(P_{ij}^{cls} * P_{ij}^{loc}) )}
num_pos += len(gt_bboxes_)
positive_losses.append(
self.positive_bag_loss(matched_cls_prob, matched_box_prob))
positive_loss = torch.cat(positive_losses).sum() / max(1, num_pos)
# box_prob: P{a_{j} \in A_{+}}
box_prob = torch.stack(box_prob, dim=0)
# negative_loss:
# \sum_{j}{ FL((1 - P{a_{j} \in A_{+}}) * (1 - P_{j}^{bg})) } / n||B||
negative_loss = self.negative_bag_loss(cls_prob, box_prob).sum() / max(
1, num_pos * self.pre_anchor_topk)
losses = {
'positive_bag_loss': positive_loss,
'negative_bag_loss': negative_loss
}
return losses
def get_bboxes_single(self,
cls_scores,
bbox_preds,
mlvl_anchors,
mlvl_masks,
img_shape,
scale_factor,
cfg,
rescale=False):
mlvl_proposals = []
for idx in range(len(cls_scores)):
rpn_cls_score = cls_scores[idx]
rpn_bbox_pred = bbox_preds[idx]
anchors = mlvl_anchors[idx]
mask = mlvl_masks[idx]
assert rpn_cls_score.size()[-2:] == rpn_bbox_pred.size()[-2:]
# if no location is kept, end.
if mask.sum() == 0:
continue
rpn_cls_score = rpn_cls_score.permute(1, 2, 0)
if self.use_sigmoid_cls:
rpn_cls_score = rpn_cls_score.reshape(-1)
scores = rpn_cls_score.sigmoid()
else:
rpn_cls_score = rpn_cls_score.reshape(-1, 2)
scores = rpn_cls_score.softmax(dim=1)[:, 1]
# filter scores, bbox_pred w.r.t. mask.
# anchors are filtered in get_anchors() beforehand.
scores = scores[mask]
rpn_bbox_pred = rpn_bbox_pred.permute(1, 2, 0).reshape(-1,
4)[mask, :]
if scores.dim() == 0:
rpn_bbox_pred = rpn_bbox_pred.unsqueeze(0)
anchors = anchors.unsqueeze(0)
scores = scores.unsqueeze(0)
# filter anchors, bbox_pred, scores w.r.t. scores
if cfg.nms_pre > 0 and scores.shape[0] > cfg.nms_pre:
_, topk_inds = scores.topk(cfg.nms_pre)
rpn_bbox_pred = rpn_bbox_pred[topk_inds, :]
anchors = anchors[topk_inds, :]
scores = scores[topk_inds]
# get proposals w.r.t. anchors and rpn_bbox_pred
proposals = delta2bbox(anchors, rpn_bbox_pred, self.target_means,
self.target_stds, img_shape)
# filter out too small bboxes
if cfg.min_bbox_size > 0:
w = proposals[:, 2] - proposals[:, 0] + 1
h = proposals[:, 3] - proposals[:, 1] + 1
valid_inds = torch.nonzero((w >= cfg.min_bbox_size) &
(h >= cfg.min_bbox_size)).squeeze()
proposals = proposals[valid_inds, :]
scores = scores[valid_inds]
proposals = torch.cat([proposals, scores.unsqueeze(-1)], dim=-1)
# NMS in current level
proposals, _ = nms(proposals, cfg.nms_thr)
proposals = proposals[:cfg.nms_post, :]
mlvl_proposals.append(proposals)
proposals = torch.cat(mlvl_proposals, 0)
if cfg.nms_across_levels:
# NMS across multi levels
proposals, _ = nms(proposals, cfg.nms_thr)
proposals = proposals[:cfg.max_num, :]
else:
scores = proposals[:, 4]
num = min(cfg.max_num, proposals.shape[0])
_, topk_inds = scores.topk(num)
proposals = proposals[topk_inds, :]
return proposals
def get_bboxes_single(self,
cls_scores,
bbox_preds,
mlvl_anchors,
mlvl_masks,
img_shape,
scale_factor,
cfg,
rescale=False):
assert len(cls_scores) == len(bbox_preds) == len(mlvl_anchors)
mlvl_bboxes = []
mlvl_scores = []
for cls_score, bbox_pred, anchors, mask in zip(cls_scores, bbox_preds,
mlvl_anchors,
mlvl_masks):
assert cls_score.size()[-2:] == bbox_pred.size()[-2:]
# if no location is kept, end.
if mask.sum() == 0:
continue
# reshape scores and bbox_pred
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)
bbox_pred = bbox_pred.permute(1, 2, 0).reshape(-1, 4)
# filter scores, bbox_pred w.r.t. mask.
# anchors are filtered in get_anchors() beforehand.
scores = scores[mask, :]
bbox_pred = bbox_pred[mask, :]
if scores.dim() == 0:
anchors = anchors.unsqueeze(0)
scores = scores.unsqueeze(0)
bbox_pred = bbox_pred.unsqueeze(0)
# filter anchors, bbox_pred, scores w.r.t. scores
nms_pre = cfg.get('nms_pre', -1)
if nms_pre > 0 and scores.shape[0] > nms_pre:
if self.use_sigmoid_cls:
max_scores, _ = scores.max(dim=1)
else:
max_scores, _ = scores[:, 1:].max(dim=1)
_, topk_inds = max_scores.topk(nms_pre)
anchors = anchors[topk_inds, :]
bbox_pred = bbox_pred[topk_inds, :]
scores = scores[topk_inds, :]
bboxes = delta2bbox(anchors, bbox_pred, self.target_means,
self.target_stds, img_shape)
mlvl_bboxes.append(bboxes)
mlvl_scores.append(scores)
mlvl_bboxes = torch.cat(mlvl_bboxes)
if rescale:
mlvl_bboxes /= mlvl_bboxes.new_tensor(scale_factor)
mlvl_scores = torch.cat(mlvl_scores)
if self.use_sigmoid_cls:
padding = mlvl_scores.new_zeros(mlvl_scores.shape[0], 1)
mlvl_scores = torch.cat([padding, mlvl_scores], dim=1)
# multi class NMS
det_bboxes, det_labels = multiclass_nms(mlvl_bboxes, mlvl_scores,
cfg.score_thr, cfg.nms,
cfg.max_per_img)
return det_bboxes, det_labels
