keras-ocr 0.5.2

A packaged and flexible version of the CRAFT text detector and Keras CRNN recognition model.

keras-ocr

This is a slightly polished and packaged version of the Keras CRNN implementation and the published CRAFT text detection model. It provides a high level API for training a text detection and OCR pipeline.

Please see the documentation for more examples, including for training a custom model.

Getting Started

Installation

# To install from master
pip install git+https://github.com/faustomorales/keras-ocr.git#egg=keras-ocr

# To install from PyPi
pip install keras-ocr

Using

The package ships with an easy-to-use implementation of the CRAFT text detection model from this repository and the CRNN recognition model from this repository.

import keras_ocr

# keras-ocr will automatically download pretrained
# weights for the detector and recognizer.
pipeline = keras_ocr.pipeline.Pipeline()

# Predictions is a list of (string, box) tuples.
predictions = pipeline.recognize(image='tests/test_image.jpg')

Comparing keras-ocr and other OCR approaches

You may be wondering how the models in this package compare to existing cloud OCR APIs. We provide some metrics below and the notebook used to compute them using the first 1,000 images in the COCO-Text validation set. We limited it to 1,000 because the Google Cloud free tier is for 1,000 calls a month at the time of this writing. As always, caveats apply:

• No guarantees apply to these numbers -- please beware and compute your own metrics independently to verify them. As of this writing, they should be considered a very rough first draft. Please open an issue if you find a mistake. In particular, the cloud APIs have a variety of options that one can use to improve their performance and the responses can be parsed in different ways. It is possible that I made some error in configuration or parsing. Again, please open an issue if you find a mistake!
• We ignore punctuation and letter case because the out-of-the-box recognizer in keras-ocr (provided by this independent repository) does not support either. Note that both AWS Rekognition and Google Cloud Vision support punctuation as well as upper and lowercase characters.
• We ignore non-English text.
• We ignore illegible text.

model	latency	precision	recall
AWS	719ms	0.45	0.48
GCP	388ms	0.53	0.58
keras-ocr (scale=2)	417ms	0.53	0.54
keras-ocr (scale=3)	699ms	0.5	0.59

• Precision and recall were computed based on an intersection over union of 50% or higher and a text similarity to ground truth of 50% or higher.
• keras-ocr latency values were computed using a Tesla P4 GPU on Google Colab. scale refers to the argument provided to keras_ocr.pipelines.Pipeline() which determines the upscaling applied to the image prior to inference.
• Latency for the cloud providers was measured with sequential requests, so you can obtain significant speed improvements by making multiple simultaneous API requests.
• Each of the entries provides a link to the JSON file containing the annotations made on each pass. You can use this with the notebook to compute metrics without having to make the API calls yourself (though you are encoraged to replicate it independently)!

Why not compare to Tesseract? In every configuration I tried, Tesseract did very poorly on this test. Tesseract performs best on scans of books, not on incidental scene text like that in this dataset.