def matmul_gather_on_zeroth_axis(params, indices, scope=None):
"""Matrix multiplication based implementation of tf.gather on zeroth axis.
TODO(rathodv, jonathanhuang): enable sparse matmul option.
Args:
params: A float32 Tensor. The tensor from which to gather values.
Must be at least rank 1.
indices: A Tensor. Must be one of the following types: int32, int64.
Must be in range [0, params.shape[0])
scope: A name for the operation (optional).
Returns:
A Tensor. Has the same type as params. Values from params gathered
from indices given by indices, with shape indices.shape + params.shape[1:].
"""
scope = scope or 'MatMulGather'
with tf.name_scope(scope):
params_shape = shape_utils.combined_static_and_dynamic_shape(params)
indices_shape = shape_utils.combined_static_and_dynamic_shape(indices)
params2d = tf.reshape(params, [params_shape[0], -1])
indicator_matrix = tf.one_hot(indices, params_shape[0])
gathered_result_flattened = tf.matmul(indicator_matrix, params2d)
return tf.reshape(gathered_result_flattened,
tf.stack(indices_shape + params_shape[1:]))
def _match_when_rows_are_non_empty():
"""Performs matching when the rows of similarity matrix are non empty.
Returns:
matches: int32 tensor indicating the row each column matches to.
"""
# Matches for each column
matches = tf.argmax(input=similarity_matrix,
axis=0,
output_type=tf.int32)
# Deal with matched and unmatched threshold
if self._matched_threshold is not None:
# Get logical indices of ignored and unmatched columns as tf.int64
matched_vals = tf.reduce_max(input_tensor=similarity_matrix,
axis=0)
below_unmatched_threshold = tf.greater(
self._unmatched_threshold, matched_vals)
between_thresholds = tf.logical_and(
tf.greater_equal(matched_vals, self._unmatched_threshold),
tf.greater(self._matched_threshold, matched_vals))
if self._negatives_lower_than_unmatched:
matches = self._set_values_using_indicator(
matches, below_unmatched_threshold, -1)
matches = self._set_values_using_indicator(
matches, between_thresholds, -2)
else:
matches = self._set_values_using_indicator(
matches, below_unmatched_threshold, -2)
matches = self._set_values_using_indicator(
matches, between_thresholds, -1)
if self._force_match_for_each_row:
similarity_matrix_shape = shape_utils.combined_static_and_dynamic_shape(
similarity_matrix)
force_match_column_ids = tf.argmax(input=similarity_matrix,
axis=1,
output_type=tf.int32)
force_match_column_indicators = tf.one_hot(
force_match_column_ids, depth=similarity_matrix_shape[1])
force_match_row_ids = tf.argmax(
input=force_match_column_indicators,
axis=0,
output_type=tf.int32)
force_match_column_mask = tf.cast(
tf.reduce_max(input_tensor=force_match_column_indicators,
axis=0), tf.bool)
final_matches = tf.where(force_match_column_mask,
force_match_row_ids, matches)
return final_matches
else:
return matches
def _match_when_rows_are_empty():
"""Performs matching when the rows of similarity matrix are empty.
When the rows are empty, all detections are false positives. So we return
a tensor of -1's to indicate that the columns do not match to any rows.
Returns:
matches: int32 tensor indicating the row each column matches to.
"""
similarity_matrix_shape = shape_utils.combined_static_and_dynamic_shape(
similarity_matrix)
return -1 * tf.ones([similarity_matrix_shape[1]], dtype=tf.int32)
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()
# To broadcast matched_anchors_mask to the same shape as
# matched_reg_targets.
matched_anchors_mask_tiled = tf.tile(
tf.expand_dims(matched_anchors_mask, 1),
[1, tf.shape(matched_reg_targets)[1]])
reg_targets = tf.where(matched_anchors_mask_tiled, matched_reg_targets,
unmatched_ignored_reg_targets)
return reg_targets, matched_gt_boxlist, matched_anchors_mask
def assign(self,
anchors,
groundtruth_boxes,
groundtruth_labels=None,
groundtruth_weights=None,
**params):
"""Assign classification and regression targets to each anchor.
For a given set of anchors and groundtruth detections, match anchors
to groundtruth_boxes and assign classification and regression targets to
each anchor as well as weights based on the resulting match (specifying,
e.g., which anchors should not contribute to training loss).
Anchors that are not matched to anything are given a classification target
of self._unmatched_cls_target which can be specified via the constructor.
Args:
anchors: a BoxList representing N anchors
groundtruth_boxes: a BoxList representing M groundtruth boxes
groundtruth_labels: a tensor of shape [M, d_1, ... d_k] with labels for
each of the ground_truth boxes. The subshape [d_1, ... d_k] can be empty
(corresponding to scalar inputs). When set to None, groundtruth_labels
assumes a binary problem where all ground_truth boxes get a positive
label (of 1).
groundtruth_weights: a float tensor of shape [M] indicating the weight to
assign to all anchors match to a particular groundtruth box. The weights
must be in [0., 1.]. If None, all weights are set to 1.
**params: Additional keyword arguments for specific implementations of the
Matcher.
Returns:
cls_targets: a float32 tensor with shape [num_anchors, d_1, d_2 ... d_k],
where the subshape [d_1, ..., d_k] is compatible with groundtruth_labels
which has shape [num_gt_boxes, d_1, d_2, ... d_k].
cls_weights: a float32 tensor with shape [num_anchors]
reg_targets: a float32 tensor with shape [num_anchors, box_code_dimension]
reg_weights: a float32 tensor with shape [num_anchors]
match: a matcher.Match object encoding the match between anchors and
groundtruth boxes, with rows corresponding to groundtruth boxes
and columns corresponding to anchors.
Raises:
ValueError: if anchors or groundtruth_boxes are not of type
box_list.BoxList
"""
if not isinstance(anchors, box_list.BoxList):
raise ValueError('anchors must be an BoxList')
if not isinstance(groundtruth_boxes, box_list.BoxList):
raise ValueError('groundtruth_boxes must be an BoxList')
if groundtruth_labels is None:
groundtruth_labels = tf.ones(
tf.expand_dims(groundtruth_boxes.num_boxes(), 0))
groundtruth_labels = tf.expand_dims(groundtruth_labels, -1)
unmatched_shape_assert = shape_utils.assert_shape_equal(
shape_utils.combined_static_and_dynamic_shape(groundtruth_labels)[1:],
shape_utils.combined_static_and_dynamic_shape(
self._unmatched_cls_target))
labels_and_box_shapes_assert = shape_utils.assert_shape_equal(
shape_utils.combined_static_and_dynamic_shape(groundtruth_labels)[:1],
shape_utils.combined_static_and_dynamic_shape(
groundtruth_boxes.get())[:1])
if groundtruth_weights is None:
num_gt_boxes = groundtruth_boxes.num_boxes_static()
if not num_gt_boxes:
num_gt_boxes = groundtruth_boxes.num_boxes()
groundtruth_weights = tf.ones([num_gt_boxes], dtype=tf.float32)
with tf.control_dependencies(
[unmatched_shape_assert, labels_and_box_shapes_assert]):
match_quality_matrix = self._similarity_calc(
groundtruth_boxes.get(), anchors.get())
match = self._matcher.match(match_quality_matrix, **params)
reg_targets = self._create_regression_targets(anchors, groundtruth_boxes,
match)
cls_targets = self._create_classification_targets(groundtruth_labels,
match)
reg_weights = self._create_regression_weights(match, groundtruth_weights)
cls_weights = self._create_classification_weights(match,
groundtruth_weights)
num_anchors = anchors.num_boxes_static()
if num_anchors is not None:
reg_targets = self._reset_target_shape(reg_targets, num_anchors)
cls_targets = self._reset_target_shape(cls_targets, num_anchors)
reg_weights = self._reset_target_shape(reg_weights, num_anchors)
cls_weights = self._reset_target_shape(cls_weights, num_anchors)
return cls_targets, cls_weights, reg_targets, reg_weights, match
