Spaces:
Sleeping
Sleeping
File size: 8,807 Bytes
938e515 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 |
# Copyright (c) Facebook, Inc. and its affiliates.
import itertools
import logging
from typing import Dict, List
import torch
from detectron2.config import configurable
from detectron2.layers import ShapeSpec, batched_nms_rotated, cat
from detectron2.structures import Instances, RotatedBoxes, pairwise_iou_rotated
from detectron2.utils.memory import retry_if_cuda_oom
from ..box_regression import Box2BoxTransformRotated
from .build import PROPOSAL_GENERATOR_REGISTRY
from .proposal_utils import _is_tracing
from .rpn import RPN
logger = logging.getLogger(__name__)
def find_top_rrpn_proposals(
proposals,
pred_objectness_logits,
image_sizes,
nms_thresh,
pre_nms_topk,
post_nms_topk,
min_box_size,
training,
):
"""
For each feature map, select the `pre_nms_topk` highest scoring proposals,
apply NMS, clip proposals, and remove small boxes. Return the `post_nms_topk`
highest scoring proposals among all the feature maps if `training` is True,
otherwise, returns the highest `post_nms_topk` scoring proposals for each
feature map.
Args:
proposals (list[Tensor]): A list of L tensors. Tensor i has shape (N, Hi*Wi*A, 5).
All proposal predictions on the feature maps.
pred_objectness_logits (list[Tensor]): A list of L tensors. Tensor i has shape (N, Hi*Wi*A).
image_sizes (list[tuple]): sizes (h, w) for each image
nms_thresh (float): IoU threshold to use for NMS
pre_nms_topk (int): number of top k scoring proposals to keep before applying NMS.
When RRPN is run on multiple feature maps (as in FPN) this number is per
feature map.
post_nms_topk (int): number of top k scoring proposals to keep after applying NMS.
When RRPN is run on multiple feature maps (as in FPN) this number is total,
over all feature maps.
min_box_size(float): minimum proposal box side length in pixels (absolute units wrt
input images).
training (bool): True if proposals are to be used in training, otherwise False.
This arg exists only to support a legacy bug; look for the "NB: Legacy bug ..."
comment.
Returns:
proposals (list[Instances]): list of N Instances. The i-th Instances
stores post_nms_topk object proposals for image i.
"""
num_images = len(image_sizes)
device = proposals[0].device
# 1. Select top-k anchor for every level and every image
topk_scores = [] # #lvl Tensor, each of shape N x topk
topk_proposals = []
level_ids = [] # #lvl Tensor, each of shape (topk,)
batch_idx = torch.arange(num_images, device=device)
for level_id, proposals_i, logits_i in zip(
itertools.count(), proposals, pred_objectness_logits
):
Hi_Wi_A = logits_i.shape[1]
if isinstance(Hi_Wi_A, torch.Tensor): # it's a tensor in tracing
num_proposals_i = torch.clamp(Hi_Wi_A, max=pre_nms_topk)
else:
num_proposals_i = min(Hi_Wi_A, pre_nms_topk)
topk_scores_i, topk_idx = logits_i.topk(num_proposals_i, dim=1)
# each is N x topk
topk_proposals_i = proposals_i[batch_idx[:, None], topk_idx] # N x topk x 5
topk_proposals.append(topk_proposals_i)
topk_scores.append(topk_scores_i)
level_ids.append(torch.full((num_proposals_i,), level_id, dtype=torch.int64, device=device))
# 2. Concat all levels together
topk_scores = cat(topk_scores, dim=1)
topk_proposals = cat(topk_proposals, dim=1)
level_ids = cat(level_ids, dim=0)
# 3. For each image, run a per-level NMS, and choose topk results.
results = []
for n, image_size in enumerate(image_sizes):
boxes = RotatedBoxes(topk_proposals[n])
scores_per_img = topk_scores[n]
lvl = level_ids
valid_mask = torch.isfinite(boxes.tensor).all(dim=1) & torch.isfinite(scores_per_img)
if not valid_mask.all():
if training:
raise FloatingPointError(
"Predicted boxes or scores contain Inf/NaN. Training has diverged."
)
boxes = boxes[valid_mask]
scores_per_img = scores_per_img[valid_mask]
lvl = lvl[valid_mask]
boxes.clip(image_size)
# filter empty boxes
keep = boxes.nonempty(threshold=min_box_size)
if _is_tracing() or keep.sum().item() != len(boxes):
boxes, scores_per_img, lvl = (boxes[keep], scores_per_img[keep], lvl[keep])
keep = batched_nms_rotated(boxes.tensor, scores_per_img, lvl, nms_thresh)
# In Detectron1, there was different behavior during training vs. testing.
# (https://github.com/facebookresearch/Detectron/issues/459)
# During training, topk is over the proposals from *all* images in the training batch.
# During testing, it is over the proposals for each image separately.
# As a result, the training behavior becomes batch-dependent,
# and the configuration "POST_NMS_TOPK_TRAIN" end up relying on the batch size.
# This bug is addressed in Detectron2 to make the behavior independent of batch size.
keep = keep[:post_nms_topk]
res = Instances(image_size)
res.proposal_boxes = boxes[keep]
res.objectness_logits = scores_per_img[keep]
results.append(res)
return results
@PROPOSAL_GENERATOR_REGISTRY.register()
class RRPN(RPN):
"""
Rotated Region Proposal Network described in :paper:`RRPN`.
"""
@configurable
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
if self.anchor_boundary_thresh >= 0:
raise NotImplementedError(
"anchor_boundary_thresh is a legacy option not implemented for RRPN."
)
@classmethod
def from_config(cls, cfg, input_shape: Dict[str, ShapeSpec]):
ret = super().from_config(cfg, input_shape)
ret["box2box_transform"] = Box2BoxTransformRotated(weights=cfg.MODEL.RPN.BBOX_REG_WEIGHTS)
return ret
@torch.no_grad()
def label_and_sample_anchors(self, anchors: List[RotatedBoxes], gt_instances: List[Instances]):
"""
Args:
anchors (list[RotatedBoxes]): anchors for each feature map.
gt_instances: the ground-truth instances for each image.
Returns:
list[Tensor]:
List of #img tensors. i-th element is a vector of labels whose length is
the total number of anchors across feature maps. Label values are in {-1, 0, 1},
with meanings: -1 = ignore; 0 = negative class; 1 = positive class.
list[Tensor]:
i-th element is a Nx5 tensor, where N is the total number of anchors across
feature maps. The values are the matched gt boxes for each anchor.
Values are undefined for those anchors not labeled as 1.
"""
anchors = RotatedBoxes.cat(anchors)
gt_boxes = [x.gt_boxes for x in gt_instances]
del gt_instances
gt_labels = []
matched_gt_boxes = []
for gt_boxes_i in gt_boxes:
"""
gt_boxes_i: ground-truth boxes for i-th image
"""
match_quality_matrix = retry_if_cuda_oom(pairwise_iou_rotated)(gt_boxes_i, anchors)
matched_idxs, gt_labels_i = retry_if_cuda_oom(self.anchor_matcher)(match_quality_matrix)
# Matching is memory-expensive and may result in CPU tensors. But the result is small
gt_labels_i = gt_labels_i.to(device=gt_boxes_i.device)
# A vector of labels (-1, 0, 1) for each anchor
gt_labels_i = self._subsample_labels(gt_labels_i)
if len(gt_boxes_i) == 0:
# These values won't be used anyway since the anchor is labeled as background
matched_gt_boxes_i = torch.zeros_like(anchors.tensor)
else:
# TODO wasted indexing computation for ignored boxes
matched_gt_boxes_i = gt_boxes_i[matched_idxs].tensor
gt_labels.append(gt_labels_i) # N,AHW
matched_gt_boxes.append(matched_gt_boxes_i)
return gt_labels, matched_gt_boxes
@torch.no_grad()
def predict_proposals(self, anchors, pred_objectness_logits, pred_anchor_deltas, image_sizes):
pred_proposals = self._decode_proposals(anchors, pred_anchor_deltas)
return find_top_rrpn_proposals(
pred_proposals,
pred_objectness_logits,
image_sizes,
self.nms_thresh,
self.pre_nms_topk[self.training],
self.post_nms_topk[self.training],
self.min_box_size,
self.training,
)
|