Converting a TensorFlow Attention OCR Model

This tutorial explains how to convert the Attention OCR (AOCR) model from the TensorFlow Attention OCR repository to the Intermediate Representation (IR).

Extracting a Model from Library

To get an AOCR model, download aocr Python library:

pip install git+

This library contains a pretrained model and allows training and running AOCR, using the command line. After installation of aocr, extract the model:

aocr export --format=frozengraph model/path/

Once extracted, the model can be found in model/path/ folder.

Converting the TensorFlow AOCR Model to IR

The original AOCR model includes the preprocessing data, which contains:

  • Decoding input data to binary format where input data is an image represented as a string.

  • Resizing binary image to working resolution.

The resized image is sent to the convolution neural network (CNN). Because Model Optimizer does not support image decoding, the preprocessing part of the model should be cut off, using the --input command-line parameter.

mo \
--input_model=model/path/frozen_graph.pb \
--input="map/TensorArrayStack/TensorArrayGatherV3:0[1,32,86,1]" \
--output "transpose_1,transpose_2" \
--output_dir path/to/ir/


  • map/TensorArrayStack/TensorArrayGatherV3:0[1 32 86 1] - name of node producing tensor after preprocessing.

  • transpose_1 - name of the node producing tensor with predicted characters.

  • transpose_2 - name of the node producing tensor with predicted characters probabilities.