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@sineeli sineeli commented Feb 10, 2025

PARSeq Model

Description of the Change

This PR adds an end-to-end scene text recognition model, PARSeq, to KerasHub. PARSeq is a ViT-based OCR model that enables iterative decoding for robust text recognition in natural scenes.

Closes the first half of #<issue_number>

Reference

For details, see Scene Text Recognition with Permuted Autoregressive Sequence Models (PARSeq paper). The model and configuration are based on the official paper and open-source implementation

Colab Notebook

Usage and numerics matching Colab:

Checklist

  • I have added all the necessary unit tests for my change.
  • I have verified that my change does not break existing code and works with all backends (TensorFlow, JAX, and PyTorch).
  • My PR is based on the latest changes of the main branch (if unsure, rebase the code).
  • I have followed the Keras Hub Model contribution guidelines in making these changes.
  • I have followed the Keras Hub API design guidelines in making these changes.
  • I have signed the Contributor License Agreement.

@abheesht17
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@sineeli - which parts of the PR are ready for review? Asking because it's still marked as draft

@sineeli
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sineeli commented Feb 20, 2025

Sure @abheesht17

First preprocessing and tokenizer these parts I think are good for reviewing, as they are the primary steps.

  1. keras_hub/src/models/parseq/parseq_tokenizer.py
  2. keras_hub/src/models/text_recognition_preprocessor.py

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Thanks for the PR! Left some comments on the tokeniser. Will take a look at the text recognition preprocessor soon.

Sorry for the delay in reviewing

Comment on lines 64 to 81
self.char_to_id = tf.lookup.StaticHashTable(
initializer=tf.lookup.KeyValueTensorInitializer(
keys=list(self._stoi.keys()),
values=list(self._stoi.values()),
key_dtype=tf.string,
value_dtype=tf.int32,
),
default_value=0,
)
self.id_to_char = tf.lookup.StaticHashTable(
initializer=tf.lookup.KeyValueTensorInitializer(
keys=list(self._stoi.values()),
values=list(self._stoi.keys()),
key_dtype=tf.int32,
value_dtype=tf.string,
),
default_value=self.pad_token,
)
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The defaults don't match. EOS is the 0th token, and pad is the len(vocabulary) - 1th token

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I recognized the same in the original code, but seems they are using EOS -> 0, BOS->len(vocabulary), but while padding they are doing BOS first and then EOS at the end.

label = tf.strings.upper(label)

label = tf.strings.regex_replace(label, self.unsupported_regex, "")
label = tf.strings.substr(label, 0, self.max_label_length)
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Why are we truncating the input to 25 characters?

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While preparing the dataset in the preprocessing itself if the label is above 25 they jus ignore that datapoint itself. Instead I truncated and we can start and end tokens instead.

Ref: https://github.com/baudm/parseq/blob/1902db043c029a7e03a3818c616c06600af574be/strhub/data/dataset.py#L112

@sineeli sineeli requested a review from sachinprasadhs May 30, 2025 21:10
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Thanks, added some comments,
could you please add a PR description by following the recent PR description template which includes Colab notebook link with end to end working demo and numerics verification.
Also add the original implementation reference in the PR description.

@sachinprasadhs sachinprasadhs added kokoro:force-run Runs Tests on GPU and removed WIP Pull requests which are work in progress and not ready yet for review. labels Jun 23, 2025
@kokoro-team kokoro-team removed the kokoro:force-run Runs Tests on GPU label Jun 23, 2025
@divyashreepathihalli
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/gemini review

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Code Review

This pull request introduces the PARSeq model, a ViT-based OCR model, to KerasHub. I've identified a few issues, including two critical bugs related to model serialization and tokenizer functionality that must be addressed. I've also found a couple of medium-severity issues regarding a typo in a layer name and a docstring example that should be corrected for clarity and maintainability.

@sachinprasadhs sachinprasadhs moved this to In Progress in KerasHub Jul 16, 2025
@sineeli sineeli added the kokoro:force-run Runs Tests on GPU label Aug 6, 2025
@kokoro-team kokoro-team removed the kokoro:force-run Runs Tests on GPU label Aug 6, 2025
@sineeli sineeli added the kokoro:force-run Runs Tests on GPU label Aug 9, 2025
@kokoro-team kokoro-team removed the kokoro:force-run Runs Tests on GPU label Aug 9, 2025
@sineeli sineeli added the kokoro:force-run Runs Tests on GPU label Aug 9, 2025
@kokoro-team kokoro-team removed the kokoro:force-run Runs Tests on GPU label Aug 9, 2025
@sineeli sineeli added the kokoro:force-run Runs Tests on GPU label Aug 9, 2025
@kokoro-team kokoro-team removed the kokoro:force-run Runs Tests on GPU label Aug 9, 2025
@sachinprasadhs sachinprasadhs changed the title [WIP] PARSeq Model PARSeq Model Aug 13, 2025
@sachinprasadhs sachinprasadhs added the kokoro:force-run Runs Tests on GPU label Aug 13, 2025
@kokoro-team kokoro-team removed the kokoro:force-run Runs Tests on GPU label Aug 13, 2025
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6 participants