def _create_tf_record_from_coco_annotations(annotations_file, image_dir,
output_path, include_masks,
num_shards):
"""Loads COCO annotation json files and converts to tf.Record format.
Args:
annotations_file: JSON file containing bounding box annotations.
image_dir: Directory containing the image files.
output_path: Path to output tf.Record file.
include_masks: Whether to include instance segmentations masks
(PNG encoded) in the result. default: False.
num_shards: number of output file shards.
"""
with contextlib2.ExitStack() as tf_record_close_stack, \
tf.compat.v1.gfile.GFile(annotations_file, 'r') as fid:
output_tfrecords = tfrecord_util.open_sharded_output_tfrecords(
tf_record_close_stack, output_path, num_shards)
groundtruth_data = json.load(fid)
images = groundtruth_data['images']
category_index = label_map_util.create_category_index(
groundtruth_data['categories'])
annotations_index = {}
if 'annotations' in groundtruth_data:
logging.info('Found groundtruth annotations. Building annotations index.')
for annotation in groundtruth_data['annotations']:
image_id = annotation['image_id']
if image_id not in annotations_index:
annotations_index[image_id] = []
annotations_index[image_id].append(annotation)
missing_annotation_count = 0
for image in images:
image_id = image['id']
if image_id not in annotations_index:
missing_annotation_count += 1
annotations_index[image_id] = []
logging.info('%d images are missing annotations.', missing_annotation_count)
total_num_annotations_skipped = 0
for idx, image in enumerate(images):
if idx % 100 == 0:
logging.info('On image %d of %d', idx, len(images))
annotations_list = annotations_index[image['id']]
_, tf_example, num_annotations_skipped = create_tf_example(
image, annotations_list, image_dir, category_index, include_masks)
total_num_annotations_skipped += num_annotations_skipped
shard_idx = idx % num_shards
output_tfrecords[shard_idx].write(tf_example.SerializeToString())
logging.info('Finished writing, skipped %d annotations.',
total_num_annotations_skipped)
def _load_object_annotations(object_annotations_file):
"""Loads object annotation JSON file."""
with tf.gfile.GFile(object_annotations_file, 'r') as fid:
obj_annotations = json.load(fid)
images = obj_annotations['images']
category_index = create_category_index(obj_annotations['categories'])
img_to_obj_annotation = collections.defaultdict(list)
logging.info('Building bounding box index.')
for annotation in obj_annotations['annotations']:
image_id = annotation['image_id']
img_to_obj_annotation[image_id].append(annotation)
missing_annotation_count = 0
for image in images:
image_id = image['id']
if image_id not in img_to_obj_annotation:
missing_annotation_count += 1
logging.info('%d images are missing bboxes.', missing_annotation_count)
return img_to_obj_annotation, category_index
