转换pb_Keras模型转换成Tensorflow模型方法

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import tensorflow as tf
from tensorflow.python.framework import graph_util
from tensorflow.python.framework import graph_io
from pathlib import Path
from absl import app
from absl import flags
from absl import logging
import keras
from keras import backend as K
from keras.models import model_from_json, model_from_yaml

K.set_learning_phase(0)
FLAGS = flags.FLAGS

flags.DEFINE_string('input_model', None, 'Path to the input model.')
flags.DEFINE_string('input_model_json', None, 'Path to the input model '
                                              'architecture in json format.')
flags.DEFINE_string('input_model_yaml', None, 'Path to the input model '
                                              'architecture in yaml format.')
flags.DEFINE_string('output_model', None, 'Path where the converted model will '
                                          'be stored.')
flags.DEFINE_boolean('save_graph_def', False,
                     'Whether to save the graphdef.pbtxt file which contains '
                     'the graph definition in ASCII format.')
flags.DEFINE_string('output_nodes_prefix', None,
                    'If set, the output nodes will be renamed to '
                    '`output_nodes_prefix`+i, where `i` will numerate the '
                    'number of of output nodes of the network.')
flags.DEFINE_boolean('quantize', False,
                     'If set, the resultant TensorFlow graph weights will be '
                     'converted from float into eight-bit equivalents. See '
                     'documentation here: '
                     'https://github.com/tensorflow/tensorflow/tree/master/tensorflow/tools/graph_transforms')
flags.DEFINE_boolean('channels_first', False,
                     'Whether channels are the first dimension of a tensor. '
                     'The default is TensorFlow behaviour where channels are '
                     'the last dimension.')
flags.DEFINE_boolean('output_meta_ckpt', False,
                     'If set to True, exports the model as .meta, .index, and '
                     '.data files, with a checkpoint file. These can be later '
                     'loaded in TensorFlow to continue training.')

flags.mark_flag_as_required('input_model')
flags.mark_flag_as_required('output_model')


def load_model(input_model_path, input_json_path=None, input_yaml_path=None):
    if not Path(input_model_path).exists():
        raise FileNotFoundError(
            'Model file `{}` does not exist.'.format(input_model_path))
    try:
        model = keras.models.load_model(input_model_path)
        return model
    except FileNotFoundError as err:
        logging.error('Input mode file (%s) does not exist.', FLAGS.input_model)
        raise err
    except ValueError as wrong_file_err:
        if input_json_path:
            if not Path(input_json_path).exists():
                raise FileNotFoundError(
                    'Model description json file `{}` does not exist.'.format(
                        input_json_path))
            try:
                model = model_from_json(open(str(input_json_path)).read())
                model.load_weights(input_model_path)
                return model
            except Exception as err:
                logging.error("Couldn't load model from json.")
                raise err
        elif input_yaml_path:
            if not Path(input_yaml_path).exists():
                raise FileNotFoundError(
                    'Model description yaml file `{}` does not exist.'.format(
                        input_yaml_path))
            try:
                model = model_from_yaml(open(str(input_yaml_path)).read())
                model.load_weights(input_model_path)
                return model
            except Exception as err:
                logging.error("Couldn't load model from yaml.")
                raise err
        else:
            logging.error(
                'Input file specified only holds the weights, and not '
                'the model definition. Save the model using '
                'model.save(filename.h5) which will contain the network '
                'architecture as well as its weights. '
                'If the model is saved using the '
                'model.save_weights(filename) function, either '
                'input_model_json or input_model_yaml flags should be set to '
                'to import the network architecture prior to loading the '
                'weights. n'
                'Check the keras documentation for more details '
                '(https://keras.io/getting-started/faq/)')
            raise wrong_file_err


def main(args):
    # If output_model path is relative and in cwd, make it absolute from root
    output_model = FLAGS.output_model
    if str(Path(output_model).parent) == '.':
        output_model = str((Path.cwd() / output_model))

    output_fld = Path(output_model).parent
    output_model_name = Path(output_model).name
    output_model_stem = Path(output_model).stem
    output_model_pbtxt_name = output_model_stem + '.pbtxt'

    # Create output directory if it does not exist
    Path(output_model).parent.mkdir(parents=True, exist_ok=True)

    if FLAGS.channels_first:
        K.set_image_data_format('channels_first')
    else:
        K.set_image_data_format('channels_last')

    model = load_model(FLAGS.input_model, FLAGS.input_model_json, FLAGS.input_model_yaml)

    # TODO(amirabdi): Support networks with multiple inputs
    orig_output_node_names = [node.op.name for node in model.outputs]
    if FLAGS.output_nodes_prefix:
        num_output = len(orig_output_node_names)
        pred = [None] * num_output
        converted_output_node_names = [None] * num_output

        # Create dummy tf nodes to rename output
        for i in range(num_output):
            converted_output_node_names[i] = '{}{}'.format(
                FLAGS.output_nodes_prefix, i)
            pred[i] = tf.identity(model.outputs[i],
                                  name=converted_output_node_names[i])
    else:
        converted_output_node_names = orig_output_node_names
    logging.info('Converted output node names are: %s',
                 str(converted_output_node_names))

    sess = K.get_session()
    if FLAGS.output_meta_ckpt:
        saver = tf.train.Saver()
        saver.save(sess, str(output_fld / output_model_stem))

    if FLAGS.save_graph_def:
        tf.train.write_graph(sess.graph.as_graph_def(), str(output_fld),
                             output_model_pbtxt_name, as_text=True)
        logging.info('Saved the graph definition in ascii format at %s',
                     str(Path(output_fld) / output_model_pbtxt_name))

    if FLAGS.quantize:
        from tensorflow.tools.graph_transforms import TransformGraph
        transforms = ["quantize_weights", "quantize_nodes"]
        transformed_graph_def = TransformGraph(sess.graph.as_graph_def(), [],
                                               converted_output_node_names,
                                               transforms)
        constant_graph = graph_util.convert_variables_to_constants(
            sess,
            transformed_graph_def,
            converted_output_node_names)
    else:
        constant_graph = graph_util.convert_variables_to_constants(
            sess,
            sess.graph.as_graph_def(),
            converted_output_node_names)

    graph_io.write_graph(constant_graph, str(output_fld), output_model_name,
                         as_text=False)
    logging.info('Saved the freezed graph at %s',
                 str(Path(output_fld) / output_model_name))


if __name__ == "__main__":
    app.run(main)


运行如下代码：
python keras_to_tensorflow.py      --input_model="path/to/keras/model.h5"      --input_model_json="path/to/keras/model.json"      --output_model="path/to/save/model.pb"