KyanChen's picture
init
f549064
raw
history blame contribute delete
No virus
11.6 kB
# Copyright (c) OpenMMLab. All rights reserved.
from typing import List, Optional, Tuple
import torch
from torch import Tensor
from mmdet.registry import MODELS
from mmdet.structures import SampleList
from mmdet.structures.bbox import bbox2roi
from mmdet.utils import ConfigType, InstanceList
from ..task_modules.samplers import SamplingResult
from ..utils.misc import unpack_gt_instances
from .standard_roi_head import StandardRoIHead
@MODELS.register_module()
class GridRoIHead(StandardRoIHead):
"""Implementation of `Grid RoI Head <https://arxiv.org/abs/1811.12030>`_
Args:
grid_roi_extractor (:obj:`ConfigDict` or dict): Config of
roi extractor.
grid_head (:obj:`ConfigDict` or dict): Config of grid head
"""
def __init__(self, grid_roi_extractor: ConfigType, grid_head: ConfigType,
**kwargs) -> None:
assert grid_head is not None
super().__init__(**kwargs)
if grid_roi_extractor is not None:
self.grid_roi_extractor = MODELS.build(grid_roi_extractor)
self.share_roi_extractor = False
else:
self.share_roi_extractor = True
self.grid_roi_extractor = self.bbox_roi_extractor
self.grid_head = MODELS.build(grid_head)
def _random_jitter(self,
sampling_results: List[SamplingResult],
batch_img_metas: List[dict],
amplitude: float = 0.15) -> List[SamplingResult]:
"""Ramdom jitter positive proposals for training.
Args:
sampling_results (List[obj:SamplingResult]): Assign results of
all images in a batch after sampling.
batch_img_metas (list[dict]): List of image information.
amplitude (float): Amplitude of random offset. Defaults to 0.15.
Returns:
list[obj:SamplingResult]: SamplingResults after random jittering.
"""
for sampling_result, img_meta in zip(sampling_results,
batch_img_metas):
bboxes = sampling_result.pos_priors
random_offsets = bboxes.new_empty(bboxes.shape[0], 4).uniform_(
-amplitude, amplitude)
# before jittering
cxcy = (bboxes[:, 2:4] + bboxes[:, :2]) / 2
wh = (bboxes[:, 2:4] - bboxes[:, :2]).abs()
# after jittering
new_cxcy = cxcy + wh * random_offsets[:, :2]
new_wh = wh * (1 + random_offsets[:, 2:])
# xywh to xyxy
new_x1y1 = (new_cxcy - new_wh / 2)
new_x2y2 = (new_cxcy + new_wh / 2)
new_bboxes = torch.cat([new_x1y1, new_x2y2], dim=1)
# clip bboxes
max_shape = img_meta['img_shape']
if max_shape is not None:
new_bboxes[:, 0::2].clamp_(min=0, max=max_shape[1] - 1)
new_bboxes[:, 1::2].clamp_(min=0, max=max_shape[0] - 1)
sampling_result.pos_priors = new_bboxes
return sampling_results
# TODO: Forward is incorrect and need to refactor.
def forward(self,
x: Tuple[Tensor],
rpn_results_list: InstanceList,
batch_data_samples: SampleList = None) -> tuple:
"""Network forward process. Usually includes backbone, neck and head
forward without any post-processing.
Args:
x (Tuple[Tensor]): Multi-level features that may have different
resolutions.
rpn_results_list (list[:obj:`InstanceData`]): List of region
proposals.
batch_data_samples (list[:obj:`DetDataSample`]): Each item contains
the meta information of each image and corresponding
annotations.
Returns
tuple: A tuple of features from ``bbox_head`` and ``mask_head``
forward.
"""
results = ()
proposals = [rpn_results.bboxes for rpn_results in rpn_results_list]
rois = bbox2roi(proposals)
# bbox head
if self.with_bbox:
bbox_results = self._bbox_forward(x, rois)
results = results + (bbox_results['cls_score'], )
if self.bbox_head.with_reg:
results = results + (bbox_results['bbox_pred'], )
# grid head
grid_rois = rois[:100]
grid_feats = self.grid_roi_extractor(
x[:len(self.grid_roi_extractor.featmap_strides)], grid_rois)
if self.with_shared_head:
grid_feats = self.shared_head(grid_feats)
self.grid_head.test_mode = True
grid_preds = self.grid_head(grid_feats)
results = results + (grid_preds, )
# mask head
if self.with_mask:
mask_rois = rois[:100]
mask_results = self._mask_forward(x, mask_rois)
results = results + (mask_results['mask_preds'], )
return results
def loss(self, x: Tuple[Tensor], rpn_results_list: InstanceList,
batch_data_samples: SampleList, **kwargs) -> dict:
"""Perform forward propagation and loss calculation of the detection
roi on the features of the upstream network.
Args:
x (tuple[Tensor]): List of multi-level img features.
rpn_results_list (list[:obj:`InstanceData`]): List of region
proposals.
batch_data_samples (list[:obj:`DetDataSample`]): The batch
data samples. It usually includes information such
as `gt_instance` or `gt_panoptic_seg` or `gt_sem_seg`.
Returns:
dict[str, Tensor]: A dictionary of loss components
"""
assert len(rpn_results_list) == len(batch_data_samples)
outputs = unpack_gt_instances(batch_data_samples)
(batch_gt_instances, batch_gt_instances_ignore,
batch_img_metas) = outputs
# assign gts and sample proposals
num_imgs = len(batch_data_samples)
sampling_results = []
for i in range(num_imgs):
# rename rpn_results.bboxes to rpn_results.priors
rpn_results = rpn_results_list[i]
rpn_results.priors = rpn_results.pop('bboxes')
assign_result = self.bbox_assigner.assign(
rpn_results, batch_gt_instances[i],
batch_gt_instances_ignore[i])
sampling_result = self.bbox_sampler.sample(
assign_result,
rpn_results,
batch_gt_instances[i],
feats=[lvl_feat[i][None] for lvl_feat in x])
sampling_results.append(sampling_result)
losses = dict()
# bbox head loss
if self.with_bbox:
bbox_results = self.bbox_loss(x, sampling_results, batch_img_metas)
losses.update(bbox_results['loss_bbox'])
# mask head forward and loss
if self.with_mask:
mask_results = self.mask_loss(x, sampling_results,
bbox_results['bbox_feats'],
batch_gt_instances)
losses.update(mask_results['loss_mask'])
return losses
def bbox_loss(self,
x: Tuple[Tensor],
sampling_results: List[SamplingResult],
batch_img_metas: Optional[List[dict]] = None) -> dict:
"""Perform forward propagation and loss calculation of the bbox head on
the features of the upstream network.
Args:
x (tuple[Tensor]): List of multi-level img features.
sampling_results (list[:obj:`SamplingResult`]): Sampling results.
batch_img_metas (list[dict], optional): Meta information of each
image, e.g., image size, scaling factor, etc.
Returns:
dict[str, Tensor]: Usually returns a dictionary with keys:
- `cls_score` (Tensor): Classification scores.
- `bbox_pred` (Tensor): Box energies / deltas.
- `bbox_feats` (Tensor): Extract bbox RoI features.
- `loss_bbox` (dict): A dictionary of bbox loss components.
"""
assert batch_img_metas is not None
bbox_results = super().bbox_loss(x, sampling_results)
# Grid head forward and loss
sampling_results = self._random_jitter(sampling_results,
batch_img_metas)
pos_rois = bbox2roi([res.pos_bboxes for res in sampling_results])
# GN in head does not support zero shape input
if pos_rois.shape[0] == 0:
return bbox_results
grid_feats = self.grid_roi_extractor(
x[:self.grid_roi_extractor.num_inputs], pos_rois)
if self.with_shared_head:
grid_feats = self.shared_head(grid_feats)
# Accelerate training
max_sample_num_grid = self.train_cfg.get('max_num_grid', 192)
sample_idx = torch.randperm(
grid_feats.shape[0])[:min(grid_feats.shape[0], max_sample_num_grid
)]
grid_feats = grid_feats[sample_idx]
grid_pred = self.grid_head(grid_feats)
loss_grid = self.grid_head.loss(grid_pred, sample_idx,
sampling_results, self.train_cfg)
bbox_results['loss_bbox'].update(loss_grid)
return bbox_results
def predict_bbox(self,
x: Tuple[Tensor],
batch_img_metas: List[dict],
rpn_results_list: InstanceList,
rcnn_test_cfg: ConfigType,
rescale: bool = False) -> InstanceList:
"""Perform forward propagation of the bbox head and predict detection
results on the features of the upstream network.
Args:
x (tuple[Tensor]): Feature maps of all scale level.
batch_img_metas (list[dict]): List of image information.
rpn_results_list (list[:obj:`InstanceData`]): List of region
proposals.
rcnn_test_cfg (:obj:`ConfigDict`): `test_cfg` of R-CNN.
rescale (bool): If True, return boxes in original image space.
Defaults to False.
Returns:
list[:obj:`InstanceData`]: 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).
"""
results_list = super().predict_bbox(
x,
batch_img_metas=batch_img_metas,
rpn_results_list=rpn_results_list,
rcnn_test_cfg=rcnn_test_cfg,
rescale=False)
grid_rois = bbox2roi([res.bboxes for res in results_list])
if grid_rois.shape[0] != 0:
grid_feats = self.grid_roi_extractor(
x[:len(self.grid_roi_extractor.featmap_strides)], grid_rois)
if self.with_shared_head:
grid_feats = self.shared_head(grid_feats)
self.grid_head.test_mode = True
grid_preds = self.grid_head(grid_feats)
results_list = self.grid_head.predict_by_feat(
grid_preds=grid_preds,
results_list=results_list,
batch_img_metas=batch_img_metas,
rescale=rescale)
return results_list