def test_with_descending_sorting(self):
sorted_boxlist = np_box_list_ops.sort_by_field(self.boxlist, 'scores')
expected_boxes = np.array(
[[14.0, 14.0, 15.0, 15.0], [3.0, 4.0, 6.0, 8.0],
[0.0, 0.0, 20.0, 20.0]],
dtype=float)
self.assertAllClose(expected_boxes, sorted_boxlist.get())
expected_scores = np.array([0.9, 0.5, 0.4], dtype=float)
self.assertAllClose(expected_scores,
sorted_boxlist.get_field('scores'))
def sort_by_field(box_mask_list,
field,
order=np_box_list_ops.SortOrder.DESCEND):
"""Sort boxes and associated fields according to a scalar field.
A common use case is reordering the boxes according to descending scores.
Args:
box_mask_list: BoxMaskList holding N boxes.
field: A BoxMaskList field for sorting and reordering the BoxMaskList.
order: (Optional) 'descend' or 'ascend'. Default is descend.
Returns:
sorted_box_mask_list: A sorted BoxMaskList with the field in the specified
order.
"""
return box_list_to_box_mask_list(
np_box_list_ops.sort_by_field(boxlist=box_mask_list,
field=field,
order=order))
def multi_class_non_max_suppression(box_mask_list, score_thresh, iou_thresh,
max_output_size):
"""Multi-class version of non maximum suppression.
This op greedily selects a subset of detection bounding boxes, pruning
away boxes that have high IOU (intersection over union) overlap (> thresh)
with already selected boxes. It operates independently for each class for
which scores are provided (via the scores field of the input box_list),
pruning boxes with score less than a provided threshold prior to
applying NMS.
Args:
box_mask_list: np_box_mask_list.BoxMaskList holding N boxes. Must contain a
'scores' field representing detection scores. This scores field is a
tensor that can be 1 dimensional (in the case of a single class) or
2-dimensional, in which case we assume that it takes the
shape [num_boxes, num_classes]. We further assume that this rank is known
statically and that scores.shape[1] is also known (i.e., the number of
classes is fixed and known at graph construction time).
score_thresh: scalar threshold for score (low scoring boxes are removed).
iou_thresh: scalar threshold for IOU (boxes that that high IOU overlap
with previously selected boxes are removed).
max_output_size: maximum number of retained boxes per class.
Returns:
a box_mask_list holding M boxes with a rank-1 scores field representing
corresponding scores for each box with scores sorted in decreasing order
and a rank-1 classes field representing a class label for each box.
Raises:
ValueError: if iou_thresh is not in [0, 1] or if input box_mask_list does
not have a valid scores field.
"""
if not 0 <= iou_thresh <= 1.0:
raise ValueError('thresh must be between 0 and 1')
if not isinstance(box_mask_list, np_box_mask_list.BoxMaskList):
raise ValueError('box_mask_list must be a box_mask_list')
if not box_mask_list.has_field('scores'):
raise ValueError('input box_mask_list must have \'scores\' field')
scores = box_mask_list.get_field('scores')
if len(scores.shape) == 1:
scores = np.reshape(scores, [-1, 1])
elif len(scores.shape) == 2:
if scores.shape[1] is None:
raise ValueError(
'scores field must have statically defined second '
'dimension')
else:
raise ValueError('scores field must be of rank 1 or 2')
num_boxes = box_mask_list.num_boxes()
num_scores = scores.shape[0]
num_classes = scores.shape[1]
if num_boxes != num_scores:
raise ValueError('Incorrect scores field length: actual vs expected.')
selected_boxes_list = []
for class_idx in range(num_classes):
box_mask_list_and_class_scores = np_box_mask_list.BoxMaskList(
box_data=box_mask_list.get(), mask_data=box_mask_list.get_masks())
class_scores = np.reshape(scores[0:num_scores, class_idx], [-1])
box_mask_list_and_class_scores.add_field('scores', class_scores)
box_mask_list_filt = filter_scores_greater_than(
box_mask_list_and_class_scores, score_thresh)
nms_result = non_max_suppression(box_mask_list_filt,
max_output_size=max_output_size,
iou_threshold=iou_thresh,
score_threshold=score_thresh)
nms_result.add_field(
'classes',
np.zeros_like(nms_result.get_field('scores')) + class_idx)
selected_boxes_list.append(nms_result)
selected_boxes = np_box_list_ops.concatenate(selected_boxes_list)
sorted_boxes = np_box_list_ops.sort_by_field(selected_boxes, 'scores')
return box_list_to_box_mask_list(boxlist=sorted_boxes)
def test_with_invalid_sorting_order(self):
with self.assertRaises(ValueError):
np_box_list_ops.sort_by_field(self.boxlist, 'scores', 'Descending')
def test_with_invalid_field(self):
with self.assertRaises(ValueError):
np_box_list_ops.sort_by_field(self.boxlist, 'objectness')
with self.assertRaises(ValueError):
np_box_list_ops.sort_by_field(self.boxlist, 'labels')