def label_anchors(self, gt_boxes, gt_labels):
"""Labels anchors with ground truth inputs.
Args:
gt_boxes: A float tensor with shape [N, 4] representing groundtruth boxes.
For each row, it stores [y0, x0, y1, x1] for four corners of a box.
gt_labels: A integer tensor with shape [N, 1] representing groundtruth
classes.
Returns:
score_targets_dict: ordered dictionary with keys
[min_level, min_level+1, ..., max_level]. The values are tensor with
shape [height_l, width_l, num_anchors]. The height_l and width_l
represent the dimension of class logits at l-th level.
box_targets_dict: ordered dictionary with keys
[min_level, min_level+1, ..., max_level]. The values are tensor with
shape [height_l, width_l, num_anchors * 4]. The height_l and
width_l represent the dimension of bounding box regression output at
l-th level.
"""
gt_box_list = box_list.BoxList(gt_boxes)
anchor_box_list = box_list.BoxList(self._anchors.boxes)
# cls_targets, cls_weights, box_weights are not used
_, _, box_targets, _, matches = self._target_assigner.assign(
anchor_box_list, gt_box_list, gt_labels)
# score_targets contains the subsampled positive and negative anchors.
score_targets, _, _ = self._get_rpn_samples(matches.match_results)
# Unpack labels.
score_targets_dict = self._anchors.unpack_labels(score_targets)
box_targets_dict = self._anchors.unpack_labels(box_targets)
return score_targets_dict, box_targets_dict
def scale_boxes_to_pixel_coordinates(image, boxes, keypoints=None):
"""Scales boxes from normalized to pixel coordinates.
Args:
image: A 3D float32 tensor of shape [height, width, channels].
boxes: A 2D float32 tensor of shape [num_boxes, 4] containing the bounding
boxes in normalized coordinates. Each row is of the form
[ymin, xmin, ymax, xmax].
keypoints: (optional) rank 3 float32 tensor with shape
[num_instances, num_keypoints, 2]. The keypoints are in y-x normalized
coordinates.
Returns:
image: unchanged input image.
scaled_boxes: a 2D float32 tensor of shape [num_boxes, 4] containing the
bounding boxes in pixel coordinates.
scaled_keypoints: a 3D float32 tensor with shape
[num_instances, num_keypoints, 2] containing the keypoints in pixel
coordinates.
"""
boxlist = box_list.BoxList(boxes)
image_height = tf.shape(input=image)[0]
image_width = tf.shape(input=image)[1]
scaled_boxes = box_list_scale(boxlist, image_height, image_width).get()
result = [image, scaled_boxes]
if keypoints is not None:
scaled_keypoints = keypoint_scale(keypoints, image_height, image_width)
result.append(scaled_keypoints)
return tuple(result)
def _decode(self, rel_codes, anchors):
"""Decode relative codes to boxes.
Args:
rel_codes: a tensor representing N anchor-encoded boxes.
anchors: BoxList of anchors.
Returns:
boxes: BoxList holding N bounding boxes.
"""
ycenter_a, xcenter_a, ha, wa = anchors.get_center_coordinates_and_sizes()
ty, tx, th, tw = tf.unstack(tf.transpose(a=rel_codes))
if self._scale_factors:
ty /= self._scale_factors[0]
tx /= self._scale_factors[1]
th /= self._scale_factors[2]
tw /= self._scale_factors[3]
w = tf.exp(tw) * wa
h = tf.exp(th) * ha
ycenter = ty * ha + ycenter_a
xcenter = tx * wa + xcenter_a
ymin = ycenter - h / 2.
xmin = xcenter - w / 2.
ymax = ycenter + h / 2.
xmax = xcenter + w / 2.
return box_list.BoxList(tf.transpose(a=tf.stack([ymin, xmin, ymax, xmax])))
def _create_regression_targets(self, anchors, groundtruth_boxes, match):
"""Returns a regression target for each anchor.
Args:
anchors: a BoxList representing N anchors
groundtruth_boxes: a BoxList representing M groundtruth_boxes
match: a matcher.Match object
Returns:
reg_targets: a float32 tensor with shape [N, box_code_dimension]
"""
matched_gt_boxes = match.gather_based_on_match(
groundtruth_boxes.get(),
unmatched_value=tf.zeros(4),
ignored_value=tf.zeros(4))
matched_gt_boxlist = box_list.BoxList(matched_gt_boxes)
if groundtruth_boxes.has_field(KEYPOINTS_FIELD_NAME):
groundtruth_keypoints = groundtruth_boxes.get_field(
KEYPOINTS_FIELD_NAME)
matched_keypoints = match.gather_based_on_match(
groundtruth_keypoints,
unmatched_value=tf.zeros(
groundtruth_keypoints.get_shape()[1:]),
ignored_value=tf.zeros(groundtruth_keypoints.get_shape()[1:]))
matched_gt_boxlist.add_field(KEYPOINTS_FIELD_NAME,
matched_keypoints)
matched_reg_targets = self._box_coder.encode(matched_gt_boxlist,
anchors)
match_results_shape = shape_utils.combined_static_and_dynamic_shape(
match.match_results)
# Zero out the unmatched and ignored regression targets.
unmatched_ignored_reg_targets = tf.tile(
self._default_regression_target(), [match_results_shape[0], 1])
matched_anchors_mask = match.matched_column_indicator()
matched_anchors_mask = tf.expand_dims(matched_anchors_mask, axis=1)
matched_anchors_mask = tf.broadcast_to(
matched_anchors_mask, shape=matched_reg_targets.get_shape())
reg_targets = tf.where(matched_anchors_mask, matched_reg_targets,
unmatched_ignored_reg_targets)
return reg_targets
def box_list_scale(boxlist, y_scale, x_scale, scope=None):
"""scale box coordinates in x and y dimensions.
Args:
boxlist: BoxList holding N boxes
y_scale: (float) scalar tensor
x_scale: (float) scalar tensor
scope: name scope.
Returns:
boxlist: BoxList holding N boxes
"""
y_scale = tf.cast(y_scale, tf.float32)
x_scale = tf.cast(x_scale, tf.float32)
y_min, x_min, y_max, x_max = tf.split(
value=boxlist.get(), num_or_size_splits=4, axis=1)
y_min = y_scale * y_min
y_max = y_scale * y_max
x_min = x_scale * x_min
x_max = x_scale * x_max
scaled_boxlist = box_list.BoxList(
tf.concat([y_min, x_min, y_max, x_max], 1))
return _copy_extra_fields(scaled_boxlist, boxlist)