def variable_summaries(var, scope=""):
"""Attach a lot of summaries to a Tensor (for TensorBoard visualization)."""
with tf.name_scope(scope):
with tf.name_scope("summaries"):
mean = tf.reduce_mean(var)
tf.summary.scalar("mean", mean)
with tf.name_scope("stddev"):
stddev = tf.sqrt(tf.reduce_mean(tf.square(var - mean)))
tf.summary.scalar("stddev", stddev)
tf.summary.scalar("max", tf.reduce_max(var))
tf.summary.scalar("min", tf.reduce_min(var))
tf.summary.histogram("histogram", var)
def focal_loss(logits, targets, alpha, gamma, normalizer):
"""Compute the focal loss between `logits` and the golden `target` values.
Focal loss = -(1-alpha)^gamma * log(pt)
where pt is the probability of being classified to the true class.
Args:
logits: A float32 tensor of size
[batch, height_in, width_in, num_predictions].
targets: A float32 tensor of size
[batch, height_in, width_in, num_predictions].
alpha: A float32 scalar multiplying alpha to the loss from positive examples
and (1-alpha) to the loss from negative examples.
gamma: A float32 scalar modulating loss from hard and easy examples.
normalizer: A float32 scalar normalizes the total loss from all examples.
Returns:
loss: A float32 scalar representing normalized total loss.
"""
with tf.name_scope('focal_loss'):
positive_label_mask = tf.equal(targets, 1.0)
cross_entropy = (
tf.nn.sigmoid_cross_entropy_with_logits(labels=targets, logits=logits))
probs = tf.sigmoid(logits)
probs_gt = tf.where(positive_label_mask, probs, 1.0 - probs)
# With small gamma, the implementation could produce NaN during back prop.
modulator = tf.pow(1.0 - probs_gt, gamma)
loss = modulator * cross_entropy
weighted_loss = tf.where(positive_label_mask, alpha * loss,
(1.0 - alpha) * loss)
total_loss = tf.reduce_sum(weighted_loss)
total_loss /= normalizer
return total_loss
def upsampling_tpu_compatible(data, scale):
"""Nearest neighbor upsampling TPU-compatible implementation.
This implementation is TPU compatible as opposed to
tf.image.resize_nearest_neighbor().
Args:
data: A 4D float32 tensor of shape [batch, height, width, channels].
scale: An integer multiple to scale resolution of input data.
Returns:
A 4D float32 tensor of shape [batch, height*scale, width*scale, channels].
"""
with tf.name_scope('upsampling_tpu_compatible'):
if data.get_shape().is_fully_defined():
bs, height, width, _ = [s.value for s in data.get_shape()]
else:
shape = tf.shape(data)
bs, height, width = shape[0], shape[1], shape[2]
channels = data.get_shape().as_list()[3]
# Use reshape to quickly upsample the input. The nearest pixel is selected
# implicitly via broadcasting.
data = tf.reshape(data, [bs, height, 1, width, 1, channels]) * tf.ones(
[1, 1, scale, 1, scale, 1], dtype=data.dtype)
return tf.reshape(data, [bs, height * scale, width * scale, channels])
def _dataset_parser(value):
"""Parse data to a fixed dimension input image and learning targets."""
with tf.name_scope('parser'):
data = example_decoder.decode(value)
source_id = data['source_id']
image = data['image']
boxes = data['groundtruth_boxes']
classes = data['groundtruth_classes']
classes = tf.reshape(tf.cast(classes, dtype=tf.float32),
[-1, 1])
# the image normalization is identical to Cloud TPU ResNet-50
image = tf.image.convert_image_dtype(image, dtype=tf.float32)
image = _normalize_image(image)
if params['input_rand_hflip']:
image, boxes = preprocessor.random_horizontal_flip(
image, boxes=boxes)
image_original_shape = tf.shape(image)
image, _ = preprocessor.resize_to_range(
image,
min_dimension=params['image_size'],
max_dimension=params['image_size'])
image_scale = tf.to_float(
image_original_shape[0]) / tf.to_float(tf.shape(image)[0])
image, boxes = preprocessor.scale_boxes_to_pixel_coordinates(
image, boxes, keypoints=None)
image = tf.image.pad_to_bounding_box(image, 0, 0,
params['image_size'],
params['image_size'])
(cls_targets, box_targets,
num_positives) = anchor_labeler.label_anchors(boxes, classes)
source_id = tf.string_to_number(source_id, out_type=tf.float32)
row = (image, cls_targets, box_targets, num_positives,
source_id, image_scale)
return row
def _dataset_parser(value):
"""Parse data to a fixed dimension input image and learning targets.
Args:
value: A dictionary contains an image and groundtruth annotations.
Returns:
A list of the following elements in order:
image: Image tensor that is preproessed to have normalized value and
fixed dimension [image_size, image_size, 3]
label: label tensor of the same spatial dimension as the image.
"""
with tf.name_scope('parser'):
data = example_decoder.decode(value)
image = data['image']
label = data['labels_class']
label = tf.to_int32(label)
input_processor = SegmentationInputProcessor(
image, params['image_size'], label)
# The image normalization is identical to Cloud TPU ResNet.
input_processor.normalize_image()
if self._is_training and params['input_rand_hflip']:
input_processor.random_horizontal_flip()
if self._is_training:
input_processor.set_training_random_scale_factors(
params['train_scale_min'], params['train_scale_max'])
image = input_processor.resize_and_crop_image()
# Set padding to background (class=0) during training.
if self._is_training:
label = input_processor.resize_and_crop_label(0)
else:
label = input_processor.resize_and_crop_label(
params['ignore_label'])
if params['use_bfloat16']:
image = tf.cast(image, dtype=tf.bfloat16)
return image, label
def _dataset_parser(value):
"""Parse data to a fixed dimension input image and learning targets.
Args:
value: A dictionary contains an image and groundtruth annotations.
Returns:
features: A dictionary that contains the image and auxiliary
information. The following describes {key: value} pairs in the
dictionary.
image: An image tensor that is preprocessed to have normalized value
and fixed dimension [image_size, image_size, 3]
image_info: Image information that includes the original height and
width, the scale of the processed image to the original image, and
the scaled height and width.
source_ids: Source image id. Default value -1 if the source id is
empty in the groundtruth annotation.
labels: (only for training) A dictionary that contains groundtruth
labels. The following describes {key: value} pairs in the dictionary.
score_targets_dict: An 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 objectiveness score at l-th level.
box_targets_dict: An 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_boxes: Groundtruth bounding box annotations. The box is represented
in [y1, x1, y2, x2] format. The tennsor is padded with -1 to the
fixed dimension [self._max_num_instances, 4].
gt_classes: Groundtruth classes annotations. The tennsor is padded
with -1 to the fixed dimension [self._max_num_instances].
cropped_gt_masks: Groundtruth masks cropped by the bounding box and
resized to a fixed size determined by params['gt_mask_size']
"""
with tf.name_scope('parser'):
data = example_decoder.decode(value)
image = data['image']
source_id = data['source_id']
source_id = tf.where(tf.equal(source_id, tf.constant('')),
'-1', source_id)
source_id = tf.string_to_number(source_id)
if self._mode == tf.estimator.ModeKeys.PREDICT:
input_processor = InstanceSegmentationInputProcessor(
image, image_size, params['short_side_image_size'],
params['long_side_max_image_size'])
input_processor.normalize_image()
input_processor.set_scale_factors_to_mlperf_reference_size(
)
image = input_processor.resize_and_crop_image()
if params['use_bfloat16']:
image = tf.cast(image, dtype=tf.bfloat16)
image_info = input_processor.get_image_info()
return {
'images': image,
'image_info': image_info,
'source_ids': source_id
}
# The following part is for training.
instance_masks = data['groundtruth_instance_masks']
boxes = data['groundtruth_boxes']
classes = data['groundtruth_classes']
classes = tf.reshape(tf.cast(classes, dtype=tf.float32),
[-1, 1])
if not params['use_category']:
classes = tf.cast(tf.greater(classes, 0), dtype=tf.float32)
if (params['skip_crowd_during_training']
and self._mode == tf.estimator.ModeKeys.TRAIN):
indices = tf.where(
tf.logical_not(data['groundtruth_is_crowd']))
classes = tf.gather_nd(classes, indices)
boxes = tf.gather_nd(boxes, indices)
instance_masks = tf.gather_nd(instance_masks, indices)
input_processor = InstanceSegmentationInputProcessor(
image, image_size, params['short_side_image_size'],
params['long_side_max_image_size'], boxes, classes,
instance_masks)
input_processor.normalize_image()
if params['input_rand_hflip']:
input_processor.random_horizontal_flip()
input_processor.set_scale_factors_to_mlperf_reference_size()
image = input_processor.resize_and_crop_image()
boxes, classes = input_processor.resize_and_crop_boxes()
cropped_gt_masks = input_processor.crop_gt_masks(
params['gt_mask_size'])
image_info = input_processor.get_image_info()
# Assign anchors.
is_height_short_side = tf.less(image_info[3], image_info[4])
score_targets, box_targets = tf.cond(
is_height_short_side,
lambda: anchor_labeler.label_anchors(boxes, classes),
lambda: height_long_side_anchor_labeler.label_anchors(boxes, classes)) # pylint: disable=line-too-long
# Pad groundtruth data.
boxes *= image_info[2]
boxes = pad_to_fixed_size(boxes, -1,
[self._max_num_instances, 4])
classes = pad_to_fixed_size(classes, -1,
[self._max_num_instances, 1])
# Pads cropped_gt_masks.
cropped_gt_masks = tf.reshape(
cropped_gt_masks, [-1, (params['gt_mask_size'] + 4)**2])
cropped_gt_masks = pad_to_fixed_size(
cropped_gt_masks, -1,
[self._max_num_instances, (params['gt_mask_size'] + 4)**2])
cropped_gt_masks = tf.reshape(cropped_gt_masks, [
self._max_num_instances, params['gt_mask_size'] + 4,
params['gt_mask_size'] + 4
])
if params['use_bfloat16']:
image = tf.cast(image, dtype=tf.bfloat16)
features = {}
features['images'] = image
features['image_info'] = image_info
features['source_ids'] = source_id
labels = {}
for level in range(params['min_level'],
params['max_level'] + 1):
labels['score_targets_%d' % level] = score_targets[level]
labels['box_targets_%d' % level] = box_targets[level]
labels['gt_boxes'] = boxes
labels['gt_classes'] = classes
labels['cropped_gt_masks'] = cropped_gt_masks
return features, labels
def _dataset_parser(value):
"""Parse data to a fixed dimension input image and learning targets.
Args:
value: A dictionary contains an image and groundtruth annotations.
Returns:
image: Image tensor that is preproessed to have normalized value and
fixed dimension [image_size, image_size, 3]
cls_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.
num_positives: Number of positive anchors in the image.
source_id: Source image id. Default value -1 if the source id is empty
in the groundtruth annotation.
image_scale: Scale of the proccessed image to the original image.
boxes: Groundtruth bounding box annotations. The box is represented in
[y1, x1, y2, x2] format. The tennsor is padded with -1 to the fixed
dimension [self._max_num_instances, 4].
is_crowds: Groundtruth annotations to indicate if an annotation
represents a group of instances by value {0, 1}. The tennsor is
padded with 0 to the fixed dimension [self._max_num_instances].
areas: Groundtruth areas annotations. The tennsor is padded with -1
to the fixed dimension [self._max_num_instances].
classes: Groundtruth classes annotations. The tennsor is padded with -1
to the fixed dimension [self._max_num_instances].
"""
with tf.name_scope('parser'):
data = example_decoder.decode(value)
source_id = data['source_id']
image = data['image']
boxes = data['groundtruth_boxes']
classes = data['groundtruth_classes']
classes = tf.reshape(tf.cast(classes, dtype=tf.float32),
[-1, 1])
areas = data['groundtruth_area']
is_crowds = data['groundtruth_is_crowd']
classes = tf.reshape(tf.cast(classes, dtype=tf.float32),
[-1, 1])
if params['skip_crowd_during_training'] and self._is_training:
indices = tf.where(
tf.logical_not(data['groundtruth_is_crowd']))
classes = tf.gather_nd(classes, indices)
boxes = tf.gather_nd(boxes, indices)
# NOTE: The autoaugment method works best when used alongside the
# standard horizontal flipping of images along with size jittering
# and normalization.
if params.get('autoaugment_policy',
None) and self._is_training:
image, boxes = autoaugment.distort_image_with_autoaugment(
image, boxes, params['autoaugment_policy'])
input_processor = DetectionInputProcessor(
image, params['image_size'], boxes, classes)
input_processor.normalize_image()
if self._is_training and params['input_rand_hflip']:
input_processor.random_horizontal_flip()
if self._is_training:
input_processor.set_training_random_scale_factors(
params['train_scale_min'], params['train_scale_max'])
else:
input_processor.set_scale_factors_to_output_size()
image = input_processor.resize_and_crop_image()
boxes, classes = input_processor.resize_and_crop_boxes()
# Assign anchors.
(cls_targets, box_targets,
num_positives) = anchor_labeler.label_anchors(boxes, classes)
source_id = tf.where(tf.equal(source_id, tf.constant('')),
'-1', source_id)
source_id = tf.string_to_number(source_id)
# Pad groundtruth data for evaluation.
image_scale = input_processor.image_scale_to_original
boxes *= image_scale
is_crowds = tf.cast(is_crowds, dtype=tf.float32)
boxes = pad_to_fixed_size(boxes, -1,
[self._max_num_instances, 4])
is_crowds = pad_to_fixed_size(is_crowds, 0,
[self._max_num_instances, 1])
areas = pad_to_fixed_size(areas, -1,
[self._max_num_instances, 1])
classes = pad_to_fixed_size(classes, -1,
[self._max_num_instances, 1])
if params['use_bfloat16']:
image = tf.cast(image, dtype=tf.bfloat16)
return (image, cls_targets, box_targets, num_positives,
source_id, image_scale, boxes, is_crowds, areas,
classes)
def estimator_metric_fn(self, detections, image_scale):
"""Constructs the metric function for tf.TPUEstimator.
For each metric, we return the evaluation op and an update op; the update op
is shared across all metrics and simply appends the set of detections to the
`self.detections` list. The metric op is invoked after all examples have
been seen and computes the aggregate COCO metrics. Please find details API
in: https://www.tensorflow.org/api_docs/python/tf/contrib/learn/MetricSpec
Args:
detections: detection results in a tensor with each row representing
[image_id, x, y, width, height, score, class]
image_scale: a float tensor representing the scale between original image
and input image for the detector. It is used to rescale detections for
evaluating with the original groundtruth annotations.
Returns:
metrics_dict: A dictionary mapping from evaluation name to a tuple of
operations (`metric_op`, `update_op`). `update_op` appends the
detections for the metric to the `self.detections` list.
"""
def _evaluate():
"""Evaluates with detections from all images with COCO API.
Returns:
coco_metric: float numpy array with shape [12] representing the
coco-style evaluation metrics.
"""
detections = np.array(self.detections)
image_ids = list(set(detections[:, 0]))
coco_dt = self.coco_gt.loadRes(detections)
coco_eval = COCOeval(self.coco_gt, coco_dt)
coco_eval.params.imgIds = image_ids
coco_eval.evaluate()
coco_eval.accumulate()
coco_eval.summarize()
coco_metrics = coco_eval.stats
# clean self.detections after evaluation is done.
# this makes sure the next evaluation will start with an empty list of
# self.detections.
self.detections = []
return np.array(coco_metrics, dtype=np.float32)
def _update_op(detections, image_scale):
"""Extends self.detections with the detection results in one image.
Args:
detections: detection results in a tensor with each row representing
[image_id, x, y, width, height, score, class]
image_scale: a float tensor representing the scale between original image
and input image for the detector. It is used to rescale detections for
evaluating with the original groundtruth annotations.
"""
detections[:, 1:5] *= image_scale
self.detections.extend(detections)
with tf.name_scope('coco_metric'):
update_op = tf.py_func(_update_op, [detections, image_scale], [])
metrics = tf.py_func(_evaluate, [], tf.float32)
metrics_dict = {}
for i, name in enumerate(self.metric_names):
metrics_dict[name] = (metrics[i], update_op)
return metrics_dict