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# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved. | |
import torch | |
from .bounding_box import BoxList | |
from maskrcnn_benchmark.layers import nms as _box_nms | |
from maskrcnn_benchmark.layers import ml_nms as _box_ml_nms | |
def boxlist_nms(boxlist, nms_thresh, max_proposals=-1, score_field="score"): | |
""" | |
Performs non-maximum suppression on a boxlist, with scores specified | |
in a boxlist field via score_field. | |
Arguments: | |
boxlist(BoxList) | |
nms_thresh (float) | |
max_proposals (int): if > 0, then only the top max_proposals are kept | |
after non-maxium suppression | |
score_field (str) | |
""" | |
if nms_thresh <= 0: | |
return boxlist | |
mode = boxlist.mode | |
boxlist = boxlist.convert("xyxy") | |
boxes = boxlist.bbox | |
score = boxlist.get_field(score_field) | |
keep = _box_nms(boxes, score, nms_thresh) | |
if max_proposals > 0: | |
keep = keep[:max_proposals] | |
boxlist = boxlist[keep] | |
return boxlist.convert(mode) | |
def boxlist_ml_nms(boxlist, nms_thresh, max_proposals=-1, score_field="scores", label_field="labels"): | |
""" | |
Performs non-maximum suppression on a boxlist, with scores specified | |
in a boxlist field via score_field. | |
Arguments: | |
boxlist(BoxList) | |
nms_thresh (float) | |
max_proposals (int): if > 0, then only the top max_proposals are kept | |
after non-maximum suppression | |
score_field (str) | |
""" | |
if nms_thresh <= 0: | |
return boxlist | |
mode = boxlist.mode | |
boxlist = boxlist.convert("xyxy") | |
boxes = boxlist.bbox | |
scores = boxlist.get_field(score_field) | |
labels = boxlist.get_field(label_field) | |
if boxes.device == torch.device("cpu"): | |
keep = [] | |
unique_labels = torch.unique(labels) | |
print(unique_labels) | |
for j in unique_labels: | |
inds = (labels == j).nonzero().view(-1) | |
scores_j = scores[inds] | |
boxes_j = boxes[inds, :].view(-1, 4) | |
keep_j = _box_nms(boxes_j, scores_j, nms_thresh) | |
keep += keep_j | |
else: | |
keep = _box_ml_nms(boxes, scores, labels.float(), nms_thresh) | |
if max_proposals > 0: | |
keep = keep[:max_proposals] | |
boxlist = boxlist[keep] | |
return boxlist.convert(mode) | |
def remove_small_boxes(boxlist, min_size): | |
""" | |
Only keep boxes with both sides >= min_size | |
Arguments: | |
boxlist (Boxlist) | |
min_size (int) | |
""" | |
# WORK AROUND: work around unbind using split + squeeze. | |
xywh_boxes = boxlist.convert("xywh").bbox | |
_, _, ws, hs = xywh_boxes.split(1, dim=1) | |
ws = ws.squeeze(1) | |
hs = hs.squeeze(1) | |
keep = ((ws >= min_size) & (hs >= min_size)).nonzero().squeeze(1) | |
return boxlist[keep] | |
# implementation from https://github.com/kuangliu/torchcv/blob/master/torchcv/utils/box.py | |
# with slight modifications | |
def boxlist_iou(boxlist1, boxlist2): | |
"""Compute the intersection over union of two set of boxes. | |
The box order must be (xmin, ymin, xmax, ymax). | |
Arguments: | |
box1: (BoxList) bounding boxes, sized [N,4]. | |
box2: (BoxList) bounding boxes, sized [M,4]. | |
Returns: | |
(tensor) iou, sized [N,M]. | |
Reference: | |
https://github.com/chainer/chainercv/blob/master/chainercv/utils/bbox/bbox_iou.py | |
""" | |
if boxlist1.size != boxlist2.size: | |
raise RuntimeError("boxlists should have same image size, got {}, {}".format(boxlist1, boxlist2)) | |
N = len(boxlist1) | |
M = len(boxlist2) | |
area1 = boxlist1.area() | |
area2 = boxlist2.area() | |
box1, box2 = boxlist1.bbox, boxlist2.bbox | |
lt = torch.max(box1[:, None, :2], box2[:, :2]) # [N,M,2] | |
rb = torch.min(box1[:, None, 2:], box2[:, 2:]) # [N,M,2] | |
TO_REMOVE = 1 | |
wh = (rb - lt + TO_REMOVE).clamp(min=0) # [N,M,2] | |
inter = wh[:, :, 0] * wh[:, :, 1] # [N,M] | |
iou = inter / (area1[:, None] + area2 - inter) | |
return iou | |
# TODO redundant, remove | |
def _cat(tensors, dim=0): | |
""" | |
Efficient version of torch.cat that avoids a copy if there is only a single element in a list | |
""" | |
assert isinstance(tensors, (list, tuple)) | |
if len(tensors) == 1: | |
return tensors[0] | |
if isinstance(tensors[0], torch.Tensor): | |
return torch.cat(tensors, dim) | |
else: | |
return cat_boxlist(tensors) | |
def cat_boxlist(bboxes): | |
""" | |
Concatenates a list of BoxList (having the same image size) into a | |
single BoxList | |
Arguments: | |
bboxes (list[BoxList]) | |
""" | |
assert isinstance(bboxes, (list, tuple)) | |
assert all(isinstance(bbox, BoxList) for bbox in bboxes) | |
size = bboxes[0].size | |
assert all(bbox.size == size for bbox in bboxes) | |
mode = bboxes[0].mode | |
assert all(bbox.mode == mode for bbox in bboxes) | |
fields = set(bboxes[0].fields()) | |
assert all(set(bbox.fields()) == fields for bbox in bboxes) | |
cat_boxes = BoxList(_cat([bbox.bbox for bbox in bboxes], dim=0), size, mode) | |
for field in fields: | |
data = _cat([bbox.get_field(field) for bbox in bboxes], dim=0) | |
cat_boxes.add_field(field, data) | |
return cat_boxes | |
def getUnionBBox(aBB, bBB, margin=10): | |
assert aBB.size == bBB.size | |
assert aBB.mode == bBB.mode | |
ih, iw = aBB.size | |
union_boxes = torch.cat( | |
[ | |
(torch.min(aBB.bbox[:, [0, 1]], bBB.bbox[:, [0, 1]]) - margin).clamp(min=0), | |
(torch.max(aBB.bbox[:, [2]], bBB.bbox[:, [2]]) + margin).clamp(max=iw), | |
(torch.max(aBB.bbox[:, [3]], bBB.bbox[:, [3]]) + margin).clamp(max=ih), | |
], | |
dim=1, | |
) | |
return BoxList(union_boxes, aBB.size, mode=aBB.mode) | |