Convert TensorFlow CRNN Model

This tutorial explains how to convert a CRNN model to Intermediate Representation (IR).

On GitHub*, you can find several public versions of TensorFlow* CRNN model implementation. This tutorial explains how to convert the model from the repository to IR. If you have another implementation of CRNN model, you can convert it to IR in similar way: you need to get inference graph and run the Model Optimizer on it.

To convert this model to the IR:

Step 1. Clone this GitHub repository and checkout the commit:

  1. Clone repository:

    git clone
  2. Checkout necessary commit:

    git checkout 64f1f1867bffaacfeacc7a80eebf5834a5726122

Step 2. Train the model using framework or use the pre-trained checkpoint provided in this repository.

Step 3. Create an inference graph:

  1. Go to the CRNN_Tensorflow directory with the cloned repository:

    cd path/to/CRNN_Tensorflow
  2. Add CRNN_Tensorflow folder to PYTHONPATH.

    • For Linux* OS:

      export PYTHONPATH="${PYTHONPATH}:/path/to/CRNN_Tensorflow/"
    • For Windows* OS add /path/to/CRNN_Tensorflow/ to the PYTHONPATH environment variable in settings.

  3. Open the tools/ script. After saver.restore(sess=sess, save_path=weights_path) line, add the following code:

    import tensorflow as tf
    from tensorflow.python.framework import graph_io
    frozen = tf.compat.v1.graph_util.convert_variables_to_constants(sess, sess.graph_def, ['shadow/LSTMLayers/transpose_time_major'])
    graph_io.write_graph(frozen, '.', 'frozen_graph.pb', as_text=False)
  4. Run the demo with the following command:

    python tools/ --image_path data/test_images/test_01.jpg --weights_path model/shadownet/shadownet_2017-10-17-11-47-46.ckpt-199999

    If you want to use your checkpoint, replace the path in the --weights_path parameter with a path to your checkpoint.

  5. In the CRNN_Tensorflow directory, you will find the inference CRNN graph frozen_graph.pb. You can use this graph with the OpenVINO toolkit to convert the model into IR and run inference.

Step 4. Convert the model into IR:

mo --input_model path/to/your/CRNN_Tensorflow/frozen_graph.pb