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formula-recognition-medium-scan-0001 (composite)

Use Case and High-Level Description

This is an im2latex composite model that recognizes latex formulas. The model uses vocabulary file vocab.json to predict sequence of latex tokens. The model is built on the ResNeXt-50 backbone with additional attention-based text recognition head.

Vocabulary file is downloaded tp corresponding model directory, <models_dir>/models/intel/formula-recognition-medium-scan-0001/formula-recognition-medium-scan-0001-im2latex-decoder/vocab.json. Model can predict big and small letters, numbers, some greek letters, trigonometric functions (e.g. cos, sin, coth), logarithmic function, sqrt and superscript.

Example of the input data

Example of the output

4 7 4 W ^ { 1 } + 7 . 1 9 o ^ { 4 } - 6 - 0 . 9 6 L ^ { 1 } y

Composite model specification

Metric

Value

im2latex_medium_photographed dataset, im2latex-match-images metric

81.5%

im2latex_medium_rendered dataset, im2latex-match-images metric

95.7%

Source framework

PyTorch*

Im2latex-match-images metric is calculated by <omz_dir>/tools/accuracy_checker/openvino/tools/accuracy_checker/metrics/im2latex_images_match.py

Encoder model specification

The formula-recognition-medium-scan-0001-encoder model is a ResNeXt-50 like backbone with some initialization layers for decoder

Metric

Value

GFlops

16.56

MParams

1.69

Inputs

Image, name: imgs, shape: 1, 3, 160, 1400 in the 1, C, H, W format, where:

  • C - number of channels

  • H - image height

  • W - image width

The expected channel order is BGR.

Outputs

  1. Name: hidden, shape: 1, 512. Initial context state of the LSTM cell.

  2. Name: context, shape: 1, 512. Initial hidden state of the LSTM cell.

  3. Name: init_0, shape: 1, 256. Initial state of the decoder.

  4. Name: row_enc_out, shape: 1, 20, 75, 512. Features from encoder that are fed to a decoder.

Decoder model specification

The formula-recognition-medium-scan-0001-decoder model is an LSTM based decoder with attention module.

Metric

Value

GFlops

1.86

MParams

2.56

Inputs

  1. Name: dec_st_c, shape: 1, 512. Current context state of the LSTM cell.

  2. Name: dec_st_h, shape: 1, 512. Current hidden state of the LSTM cell.

  3. Name: output_prev, shape: 1, 256. Current state of the decoder.

  4. Name: row_enc_out, shape: 1, 20, 175, 512. Encoded features.

  5. Name: tgt, shape: 1, 1. Index of the previous symbol.

Outputs

  1. Name: dec_st_c, shape: 1, 512. Current context state of the LSTM cell.

  2. Name: dec_st_h, shape: 1, 512. Current hidden state of the LSTM cell.

  3. Name: output, shape: 1, 256. Current state of the decoder.

  4. Name: logit, shape: 1, Vocab_Size. Classification confidence scores in the [0, 1] range for every token.

Demo usage

The model can be used in the following demos provided by the Open Model Zoo to show its capabilities:

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