ocrd-anybaseocr 1.6.0

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Document Preprocessing and Segmentation

Tools for preprocessing scanned images for OCR

Installing

• 1. Create a new venv unless you already have one

  $ python3 -m venv venv

• 2. Activate the venv

  $ source venv/bin/activate

• 3. Install with make

  $ make install

#Tools

Binarizer

Method Behaviour

This function takes a scanned colored /gray scale document image as input and do the black and white binarize image.

Usage:

ocrd-anybaseocr-binarize -m (path to METs input file) -I (Input group name) -O (Output group name) [-p (path to parameter file) -o (METs output filename)]

Example:

ocrd-anybaseocr-binarize \
   -m mets.xml \
   -I OCR-D-IMG \
   -O OCR-D-PAGE-BIN

Deskewer

Method Behaviour

This function takes a document image as input and do the skew correction of that document. The input images have to be binarized for this module to work.

Usage:

ocrd-anybaseocr-deskew -m (path to METs input file) -I (Input group name) -O (Output group name) [-p (path to parameter file) -o (METs output filename)]

Example:

ocrd-anybaseocr-deskew \
  -m mets.xml \
  -I OCR-D-PAGE-BIN \
  -O OCR-D-PAGE-DESKEW

Cropper

Method Behaviour

This function takes a document image as input and crops/selects the page content area only (that's mean remove textual noise as well as any other noise around page content area). The input image need not be binarized but should be deskewed for the module to work optimally.

Usage:

ocrd-anybaseocr-crop -m (path to METs input file) -I (Input group name) -O (Output group name) [-p (path to parameter file) -o (METs output filename)]

Example:

ocrd-anybaseocr-crop \
   -m mets.xml \
   -I OCR-D-PAGE-DESKEW \
   -O OCR-D-PAGE-CROP

Dewarper

Method Behaviour

This function takes a document image as input and make the text line straight if its curved. The input image has to be binarized for the module to work.

Usage:

ocrd-anybaseocr-dewarp -m (path to METs input file) -I (Input group name) -O (Output group name) [-p (path to parameter file) -o (METs output filename)]

Example:

CUDA_VISIBLE_DEVICES=0 ocrd-anybaseocr-dewarp \
   -m mets.xml \
   -I OCR-D-PAGE-CROP \
   -O OCR-D-PAGE-DEWARP

Text/Non-Text Segmenter

Method Behaviour

This function takes a document image as an input and separates the text and non-text part from the input document image. The module outputs 2 AlternativeImages instead of document regions, which are clipped (binarized) versions of the input image, containing either only text or only non-text components.

Usage:

ocrd-anybaseocr-tiseg -m (path to METs input file) -I (Input group name) -O (Output group name) [-p (path to parameter file) -o (METs output filename)]

Example:

ocrd-anybaseocr-tiseg \
   -m mets.xml \
   -I OCR-D-PAGE-CROP \
   -O OCR-D-PAGE-TISEG

Textline Segmenter

Method Behaviour

This function takes a cropped document image as an input and segment the image into textline images. The input image should be binarized and deskewed for the module to work.

Usage:

ocrd-anybaseocr-textline -m (path to METs input file) -I (Input group name) -O (Output group name) [-p (path to parameter file) -o (METs output filename)]

Example:

ocrd-anybaseocr-textline \
   -m mets.xml \
   -I OCR-D-PAGE-TISEG \
   -O OCR-D-PAGE-TL

Document Analyser

Method Behaviour

This function takes all the cropped document images of a single book and its corresponding text regions as input and generates the logical structure on the book level. The input image should be binarized for this module to work.

Usage:

ocrd-anybaseocr-layout-analysis -m (path to METs input file) -I (Input group name) -O (Output group name) [-p (path to parameter file) -o (METs output filename)]

Example:

ocrd-anybaseocr-layout-analysis \
   -m mets.xml \
   -I OCR-IMG \
   -O OCR-D-PAGE-BLOCK

Testing

To test the tools, download OCR-D/assets. In particular, the code is tested with the dfki-testdata dataset.

Run make test to run all tests.

License

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.