import torch
from mmdet.core import bbox2result
from mmdet.models.builder import DETECTORS
from ...core.utils import flip_tensor
from .single_stage import SingleStageDetector
[docs]@DETECTORS.register_module()
class CenterNet(SingleStageDetector):
"""Implementation of CenterNet(Objects as Points)
<https://arxiv.org/abs/1904.07850>.
"""
def __init__(self,
backbone,
neck,
bbox_head,
train_cfg=None,
test_cfg=None,
pretrained=None,
init_cfg=None):
super(CenterNet, self).__init__(backbone, neck, bbox_head, train_cfg,
test_cfg, pretrained, init_cfg)
[docs] def merge_aug_results(self, aug_results, with_nms):
"""Merge augmented detection bboxes and score.
Args:
aug_results (list[list[Tensor]]): Det_bboxes and det_labels of each
image.
with_nms (bool): If True, do nms before return boxes.
Returns:
tuple: (out_bboxes, out_labels)
"""
recovered_bboxes, aug_labels = [], []
for single_result in aug_results:
recovered_bboxes.append(single_result[0][0])
aug_labels.append(single_result[0][1])
bboxes = torch.cat(recovered_bboxes, dim=0).contiguous()
labels = torch.cat(aug_labels).contiguous()
if with_nms:
out_bboxes, out_labels = self.bbox_head._bboxes_nms(
bboxes, labels, self.bbox_head.test_cfg)
else:
out_bboxes, out_labels = bboxes, labels
return out_bboxes, out_labels
[docs] def aug_test(self, imgs, img_metas, rescale=True):
"""Augment testing of CenterNet. Aug test must have flipped image pair,
and unlike CornerNet, it will perform an averaging operation on the
feature map instead of detecting bbox.
Args:
imgs (list[Tensor]): Augmented images.
img_metas (list[list[dict]]): Meta information of each image, e.g.,
image size, scaling factor, etc.
rescale (bool): If True, return boxes in original image space.
Default: True.
Note:
``imgs`` must including flipped image pairs.
Returns:
list[list[np.ndarray]]: BBox results of each image and classes.
The outer list corresponds to each image. The inner list
corresponds to each class.
"""
img_inds = list(range(len(imgs)))
assert img_metas[0][0]['flip'] + img_metas[1][0]['flip'], (
'aug test must have flipped image pair')
aug_results = []
for ind, flip_ind in zip(img_inds[0::2], img_inds[1::2]):
flip_direction = img_metas[flip_ind][0]['flip_direction']
img_pair = torch.cat([imgs[ind], imgs[flip_ind]])
x = self.extract_feat(img_pair)
center_heatmap_preds, wh_preds, offset_preds = self.bbox_head(x)
assert len(center_heatmap_preds) == len(wh_preds) == len(
offset_preds) == 1
# Feature map averaging
center_heatmap_preds[0] = (
center_heatmap_preds[0][0:1] +
flip_tensor(center_heatmap_preds[0][1:2], flip_direction)) / 2
wh_preds[0] = (wh_preds[0][0:1] +
flip_tensor(wh_preds[0][1:2], flip_direction)) / 2
bbox_list = self.bbox_head.get_bboxes(
center_heatmap_preds,
wh_preds, [offset_preds[0][0:1]],
img_metas[ind],
rescale=rescale,
with_nms=False)
aug_results.append(bbox_list)
nms_cfg = self.bbox_head.test_cfg.get('nms_cfg', None)
if nms_cfg is None:
with_nms = False
else:
with_nms = True
bbox_list = [self.merge_aug_results(aug_results, with_nms)]
bbox_results = [
bbox2result(det_bboxes, det_labels, self.bbox_head.num_classes)
for det_bboxes, det_labels in bbox_list
]
return bbox_results