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# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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"""Tensorflow Example proto decoder for object detection.
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A decoder to decode string tensors containing serialized tensorflow.Example
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protos for object detection.
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"""
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import tensorflow as tf
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from object_detection.core import data_decoder
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from object_detection.core import standard_fields as fields
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from object_detection.protos import input_reader_pb2
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from object_detection.utils import label_map_util
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slim_example_decoder = tf.contrib.slim.tfexample_decoder
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class _ClassTensorHandler(slim_example_decoder.Tensor):
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"""An ItemHandler to fetch class ids from class text."""
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def __init__(self,
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tensor_key,
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label_map_proto_file,
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shape_keys=None,
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shape=None,
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default_value=''):
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"""Initializes the LookupTensor handler.
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Simply calls a vocabulary (most often, a label mapping) lookup.
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Args:
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tensor_key: the name of the `TFExample` feature to read the tensor from.
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label_map_proto_file: File path to a text format LabelMapProto message
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mapping class text to id.
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shape_keys: Optional name or list of names of the TF-Example feature in
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which the tensor shape is stored. If a list, then each corresponds to
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one dimension of the shape.
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shape: Optional output shape of the `Tensor`. If provided, the `Tensor` is
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reshaped accordingly.
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default_value: The value used when the `tensor_key` is not found in a
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particular `TFExample`.
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Raises:
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ValueError: if both `shape_keys` and `shape` are specified.
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"""
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name_to_id = label_map_util.get_label_map_dict(
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label_map_proto_file, use_display_name=False)
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# We use a default_value of -1, but we expect all labels to be contained
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# in the label map.
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name_to_id_table = tf.contrib.lookup.HashTable(
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initializer=tf.contrib.lookup.KeyValueTensorInitializer(
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keys=tf.constant(list(name_to_id.keys())),
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values=tf.constant(list(name_to_id.values()), dtype=tf.int64)),
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default_value=-1)
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display_name_to_id = label_map_util.get_label_map_dict(
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label_map_proto_file, use_display_name=True)
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# We use a default_value of -1, but we expect all labels to be contained
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# in the label map.
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display_name_to_id_table = tf.contrib.lookup.HashTable(
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initializer=tf.contrib.lookup.KeyValueTensorInitializer(
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keys=tf.constant(list(display_name_to_id.keys())),
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values=tf.constant(
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list(display_name_to_id.values()), dtype=tf.int64)),
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default_value=-1)
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self._name_to_id_table = name_to_id_table
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self._display_name_to_id_table = display_name_to_id_table
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super(_ClassTensorHandler, self).__init__(tensor_key, shape_keys, shape,
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default_value)
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def tensors_to_item(self, keys_to_tensors):
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unmapped_tensor = super(_ClassTensorHandler,
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self).tensors_to_item(keys_to_tensors)
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return tf.maximum(self._name_to_id_table.lookup(unmapped_tensor),
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self._display_name_to_id_table.lookup(unmapped_tensor))
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class _BackupHandler(slim_example_decoder.ItemHandler):
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"""An ItemHandler that tries two ItemHandlers in order."""
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def __init__(self, handler, backup):
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"""Initializes the BackupHandler handler.
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If the first Handler's tensors_to_item returns a Tensor with no elements,
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the second Handler is used.
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Args:
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handler: The primary ItemHandler.
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backup: The backup ItemHandler.
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Raises:
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ValueError: if either is not an ItemHandler.
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"""
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if not isinstance(handler, slim_example_decoder.ItemHandler):
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raise ValueError('Primary handler is of type %s instead of ItemHandler' %
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type(handler))
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if not isinstance(backup, slim_example_decoder.ItemHandler):
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raise ValueError(
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'Backup handler is of type %s instead of ItemHandler' % type(backup))
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self._handler = handler
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self._backup = backup
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super(_BackupHandler, self).__init__(handler.keys + backup.keys)
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def tensors_to_item(self, keys_to_tensors):
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item = self._handler.tensors_to_item(keys_to_tensors)
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return tf.cond(
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pred=tf.equal(tf.reduce_prod(tf.shape(item)), 0),
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true_fn=lambda: self._backup.tensors_to_item(keys_to_tensors),
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false_fn=lambda: item)
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class TfExampleDecoder(data_decoder.DataDecoder):
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"""Tensorflow Example proto decoder."""
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def __init__(self,
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load_instance_masks=False,
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instance_mask_type=input_reader_pb2.NUMERICAL_MASKS,
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label_map_proto_file=None,
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use_display_name=False,
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dct_method='',
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num_keypoints=0,
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num_additional_channels=0,
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load_multiclass_scores=False):
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"""Constructor sets keys_to_features and items_to_handlers.
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Args:
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load_instance_masks: whether or not to load and handle instance masks.
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instance_mask_type: type of instance masks. Options are provided in
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input_reader.proto. This is only used if `load_instance_masks` is True.
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label_map_proto_file: a file path to a
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object_detection.protos.StringIntLabelMap proto. If provided, then the
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mapped IDs of 'image/object/class/text' will take precedence over the
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existing 'image/object/class/label' ID. Also, if provided, it is
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assumed that 'image/object/class/text' will be in the data.
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use_display_name: whether or not to use the `display_name` for label
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mapping (instead of `name`). Only used if label_map_proto_file is
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provided.
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dct_method: An optional string. Defaults to None. It only takes
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effect when image format is jpeg, used to specify a hint about the
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algorithm used for jpeg decompression. Currently valid values
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are ['INTEGER_FAST', 'INTEGER_ACCURATE']. The hint may be ignored, for
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example, the jpeg library does not have that specific option.
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num_keypoints: the number of keypoints per object.
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num_additional_channels: how many additional channels to use.
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load_multiclass_scores: Whether to load multiclass scores associated with
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boxes.
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Raises:
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ValueError: If `instance_mask_type` option is not one of
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input_reader_pb2.DEFAULT, input_reader_pb2.NUMERICAL, or
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input_reader_pb2.PNG_MASKS.
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"""
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# TODO(rathodv): delete unused `use_display_name` argument once we change
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# other decoders to handle label maps similarly.
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del use_display_name
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self.keys_to_features = {
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'image/encoded':
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tf.FixedLenFeature((), tf.string, default_value=''),
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'image/format':
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tf.FixedLenFeature((), tf.string, default_value='jpeg'),
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'image/filename':
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tf.FixedLenFeature((), tf.string, default_value=''),
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'image/key/sha256':
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tf.FixedLenFeature((), tf.string, default_value=''),
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'image/source_id':
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tf.FixedLenFeature((), tf.string, default_value=''),
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'image/height':
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tf.FixedLenFeature((), tf.int64, default_value=1),
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'image/width':
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tf.FixedLenFeature((), tf.int64, default_value=1),
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# Image-level labels.
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'image/class/text':
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tf.VarLenFeature(tf.string),
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'image/class/label':
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tf.VarLenFeature(tf.int64),
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# Object boxes and classes.
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'image/object/bbox/xmin':
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tf.VarLenFeature(tf.float32),
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'image/object/bbox/xmax':
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tf.VarLenFeature(tf.float32),
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'image/object/bbox/ymin':
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tf.VarLenFeature(tf.float32),
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'image/object/bbox/ymax':
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tf.VarLenFeature(tf.float32),
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'image/object/class/label':
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tf.VarLenFeature(tf.int64),
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'image/object/class/text':
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tf.VarLenFeature(tf.string),
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'image/object/area':
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tf.VarLenFeature(tf.float32),
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'image/object/is_crowd':
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tf.VarLenFeature(tf.int64),
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'image/object/difficult':
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tf.VarLenFeature(tf.int64),
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'image/object/group_of':
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tf.VarLenFeature(tf.int64),
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'image/object/weight':
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tf.VarLenFeature(tf.float32),
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}
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# We are checking `dct_method` instead of passing it directly in order to
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# ensure TF version 1.6 compatibility.
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if dct_method:
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image = slim_example_decoder.Image(
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image_key='image/encoded',
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format_key='image/format',
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channels=3,
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dct_method=dct_method)
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additional_channel_image = slim_example_decoder.Image(
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image_key='image/additional_channels/encoded',
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format_key='image/format',
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channels=1,
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repeated=True,
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dct_method=dct_method)
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else:
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image = slim_example_decoder.Image(
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image_key='image/encoded', format_key='image/format', channels=3)
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additional_channel_image = slim_example_decoder.Image(
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image_key='image/additional_channels/encoded',
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format_key='image/format',
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channels=1,
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repeated=True)
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self.items_to_handlers = {
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fields.InputDataFields.image:
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image,
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fields.InputDataFields.source_id: (
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slim_example_decoder.Tensor('image/source_id')),
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fields.InputDataFields.key: (
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slim_example_decoder.Tensor('image/key/sha256')),
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fields.InputDataFields.filename: (
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slim_example_decoder.Tensor('image/filename')),
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# Object boxes and classes.
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fields.InputDataFields.groundtruth_boxes: (
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slim_example_decoder.BoundingBox(['ymin', 'xmin', 'ymax', 'xmax'],
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'image/object/bbox/')),
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fields.InputDataFields.groundtruth_area:
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slim_example_decoder.Tensor('image/object/area'),
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fields.InputDataFields.groundtruth_is_crowd: (
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slim_example_decoder.Tensor('image/object/is_crowd')),
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fields.InputDataFields.groundtruth_difficult: (
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slim_example_decoder.Tensor('image/object/difficult')),
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fields.InputDataFields.groundtruth_group_of: (
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slim_example_decoder.Tensor('image/object/group_of')),
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fields.InputDataFields.groundtruth_weights: (
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slim_example_decoder.Tensor('image/object/weight')),
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}
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if load_multiclass_scores:
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self.keys_to_features[
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'image/object/class/multiclass_scores'] = tf.VarLenFeature(tf.float32)
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self.items_to_handlers[fields.InputDataFields.multiclass_scores] = (
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slim_example_decoder.Tensor('image/object/class/multiclass_scores'))
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if num_additional_channels > 0:
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self.keys_to_features[
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'image/additional_channels/encoded'] = tf.FixedLenFeature(
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(num_additional_channels,), tf.string)
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self.items_to_handlers[
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fields.InputDataFields.
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image_additional_channels] = additional_channel_image
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self._num_keypoints = num_keypoints
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if num_keypoints > 0:
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self.keys_to_features['image/object/keypoint/x'] = (
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tf.VarLenFeature(tf.float32))
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self.keys_to_features['image/object/keypoint/y'] = (
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tf.VarLenFeature(tf.float32))
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self.items_to_handlers[fields.InputDataFields.groundtruth_keypoints] = (
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slim_example_decoder.ItemHandlerCallback(
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['image/object/keypoint/y', 'image/object/keypoint/x'],
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self._reshape_keypoints))
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if load_instance_masks:
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if instance_mask_type in (input_reader_pb2.DEFAULT,
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input_reader_pb2.NUMERICAL_MASKS):
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self.keys_to_features['image/object/mask'] = (
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tf.VarLenFeature(tf.float32))
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self.items_to_handlers[
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fields.InputDataFields.groundtruth_instance_masks] = (
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slim_example_decoder.ItemHandlerCallback(
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['image/object/mask', 'image/height', 'image/width'],
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self._reshape_instance_masks))
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elif instance_mask_type == input_reader_pb2.PNG_MASKS:
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self.keys_to_features['image/object/mask'] = tf.VarLenFeature(tf.string)
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self.items_to_handlers[
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fields.InputDataFields.groundtruth_instance_masks] = (
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slim_example_decoder.ItemHandlerCallback(
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['image/object/mask', 'image/height', 'image/width'],
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self._decode_png_instance_masks))
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else:
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raise ValueError('Did not recognize the `instance_mask_type` option.')
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if label_map_proto_file:
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# If the label_map_proto is provided, try to use it in conjunction with
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# the class text, and fall back to a materialized ID.
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label_handler = _BackupHandler(
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_ClassTensorHandler(
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'image/object/class/text', label_map_proto_file,
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default_value=''),
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slim_example_decoder.Tensor('image/object/class/label'))
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image_label_handler = _BackupHandler(
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_ClassTensorHandler(
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fields.TfExampleFields.image_class_text,
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label_map_proto_file,
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default_value=''),
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slim_example_decoder.Tensor(fields.TfExampleFields.image_class_label))
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else:
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label_handler = slim_example_decoder.Tensor('image/object/class/label')
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image_label_handler = slim_example_decoder.Tensor(
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fields.TfExampleFields.image_class_label)
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self.items_to_handlers[
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fields.InputDataFields.groundtruth_classes] = label_handler
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self.items_to_handlers[
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fields.InputDataFields.groundtruth_image_classes] = image_label_handler
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def decode(self, tf_example_string_tensor):
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"""Decodes serialized tensorflow example and returns a tensor dictionary.
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Args:
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tf_example_string_tensor: a string tensor holding a serialized tensorflow
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example proto.
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Returns:
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A dictionary of the following tensors.
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fields.InputDataFields.image - 3D uint8 tensor of shape [None, None, 3]
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containing image.
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fields.InputDataFields.original_image_spatial_shape - 1D int32 tensor of
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shape [2] containing shape of the image.
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fields.InputDataFields.source_id - string tensor containing original
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image id.
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fields.InputDataFields.key - string tensor with unique sha256 hash key.
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fields.InputDataFields.filename - string tensor with original dataset
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filename.
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fields.InputDataFields.groundtruth_boxes - 2D float32 tensor of shape
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[None, 4] containing box corners.
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fields.InputDataFields.groundtruth_classes - 1D int64 tensor of shape
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[None] containing classes for the boxes.
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fields.InputDataFields.groundtruth_weights - 1D float32 tensor of
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shape [None] indicating the weights of groundtruth boxes.
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fields.InputDataFields.groundtruth_area - 1D float32 tensor of shape
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[None] containing containing object mask area in pixel squared.
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fields.InputDataFields.groundtruth_is_crowd - 1D bool tensor of shape
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[None] indicating if the boxes enclose a crowd.
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Optional:
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fields.InputDataFields.image_additional_channels - 3D uint8 tensor of
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shape [None, None, num_additional_channels]. 1st dim is height; 2nd dim
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is width; 3rd dim is the number of additional channels.
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fields.InputDataFields.groundtruth_difficult - 1D bool tensor of shape
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[None] indicating if the boxes represent `difficult` instances.
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fields.InputDataFields.groundtruth_group_of - 1D bool tensor of shape
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[None] indicating if the boxes represent `group_of` instances.
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fields.InputDataFields.groundtruth_keypoints - 3D float32 tensor of
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shape [None, None, 2] containing keypoints, where the coordinates of
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the keypoints are ordered (y, x).
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fields.InputDataFields.groundtruth_instance_masks - 3D float32 tensor of
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shape [None, None, None] containing instance masks.
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fields.InputDataFields.groundtruth_image_classes - 1D uint64 of shape
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[None] containing classes for the boxes.
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fields.InputDataFields.multiclass_scores - 1D float32 tensor of shape
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[None * num_classes] containing flattened multiclass scores for
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groundtruth boxes.
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"""
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serialized_example = tf.reshape(tf_example_string_tensor, shape=[])
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decoder = slim_example_decoder.TFExampleDecoder(self.keys_to_features,
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self.items_to_handlers)
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keys = decoder.list_items()
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tensors = decoder.decode(serialized_example, items=keys)
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tensor_dict = dict(zip(keys, tensors))
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is_crowd = fields.InputDataFields.groundtruth_is_crowd
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tensor_dict[is_crowd] = tf.cast(tensor_dict[is_crowd], dtype=tf.bool)
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tensor_dict[fields.InputDataFields.image].set_shape([None, None, 3])
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tensor_dict[fields.InputDataFields.original_image_spatial_shape] = tf.shape(
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tensor_dict[fields.InputDataFields.image])[:2]
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if fields.InputDataFields.image_additional_channels in tensor_dict:
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channels = tensor_dict[fields.InputDataFields.image_additional_channels]
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channels = tf.squeeze(channels, axis=3)
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channels = tf.transpose(channels, perm=[1, 2, 0])
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tensor_dict[fields.InputDataFields.image_additional_channels] = channels
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def default_groundtruth_weights():
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return tf.ones(
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[tf.shape(tensor_dict[fields.InputDataFields.groundtruth_boxes])[0]],
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dtype=tf.float32)
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tensor_dict[fields.InputDataFields.groundtruth_weights] = tf.cond(
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tf.greater(
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tf.shape(
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tensor_dict[fields.InputDataFields.groundtruth_weights])[0],
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0), lambda: tensor_dict[fields.InputDataFields.groundtruth_weights],
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default_groundtruth_weights)
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return tensor_dict
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def _reshape_keypoints(self, keys_to_tensors):
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"""Reshape keypoints.
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The instance segmentation masks are reshaped to [num_instances,
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num_keypoints, 2].
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Args:
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keys_to_tensors: a dictionary from keys to tensors.
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Returns:
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A 3-D float tensor of shape [num_instances, num_keypoints, 2] with values
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in {0, 1}.
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"""
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y = keys_to_tensors['image/object/keypoint/y']
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if isinstance(y, tf.SparseTensor):
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y = tf.sparse_tensor_to_dense(y)
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y = tf.expand_dims(y, 1)
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x = keys_to_tensors['image/object/keypoint/x']
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if isinstance(x, tf.SparseTensor):
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x = tf.sparse_tensor_to_dense(x)
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x = tf.expand_dims(x, 1)
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keypoints = tf.concat([y, x], 1)
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keypoints = tf.reshape(keypoints, [-1, self._num_keypoints, 2])
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return keypoints
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def _reshape_instance_masks(self, keys_to_tensors):
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"""Reshape instance segmentation masks.
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The instance segmentation masks are reshaped to [num_instances, height,
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width].
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Args:
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keys_to_tensors: a dictionary from keys to tensors.
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Returns:
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A 3-D float tensor of shape [num_instances, height, width] with values
|
|
in {0, 1}.
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|
"""
|
|
height = keys_to_tensors['image/height']
|
|
width = keys_to_tensors['image/width']
|
|
to_shape = tf.cast(tf.stack([-1, height, width]), tf.int32)
|
|
masks = keys_to_tensors['image/object/mask']
|
|
if isinstance(masks, tf.SparseTensor):
|
|
masks = tf.sparse_tensor_to_dense(masks)
|
|
masks = tf.reshape(tf.to_float(tf.greater(masks, 0.0)), to_shape)
|
|
return tf.cast(masks, tf.float32)
|
|
|
|
def _decode_png_instance_masks(self, keys_to_tensors):
|
|
"""Decode PNG instance segmentation masks and stack into dense tensor.
|
|
|
|
The instance segmentation masks are reshaped to [num_instances, height,
|
|
width].
|
|
|
|
Args:
|
|
keys_to_tensors: a dictionary from keys to tensors.
|
|
|
|
Returns:
|
|
A 3-D float tensor of shape [num_instances, height, width] with values
|
|
in {0, 1}.
|
|
"""
|
|
|
|
def decode_png_mask(image_buffer):
|
|
image = tf.squeeze(
|
|
tf.image.decode_image(image_buffer, channels=1), axis=2)
|
|
image.set_shape([None, None])
|
|
image = tf.to_float(tf.greater(image, 0))
|
|
return image
|
|
|
|
png_masks = keys_to_tensors['image/object/mask']
|
|
height = keys_to_tensors['image/height']
|
|
width = keys_to_tensors['image/width']
|
|
if isinstance(png_masks, tf.SparseTensor):
|
|
png_masks = tf.sparse_tensor_to_dense(png_masks, default_value='')
|
|
return tf.cond(
|
|
tf.greater(tf.size(png_masks), 0),
|
|
lambda: tf.map_fn(decode_png_mask, png_masks, dtype=tf.float32),
|
|
lambda: tf.zeros(tf.to_int32(tf.stack([0, height, width]))))
|