ocrd-wrap 0.0.4

OCR-D wrapper for arbitrary coords-preserving image operations

ocrd_wrap

OCR-D wrapper for arbitrary coords-preserving image operations

• Introduction
• Installation
• Usage
  • OCR-D processor interface ocrd-preprocess-image
  • OCR-D processor interface ocrd-skimage-normalize
  • OCR-D processor interface ocrd-skimage-denoise-raw
  • OCR-D processor interface ocrd-skimage-binarize
  • OCR-D processor interface ocrd-skimage-denoise
• Testing

Introduction

This offers OCR-D compliant workspace processors for any image processing tools which have some (usable) CLI and do not modify/invalidate image coordinates.

It thus wraps them for OCR-D without the need to write and manage code for each of them individually (exposing/passing/documenting their parameters and usage, managing releases etc). It shifts all the burden to workflow configuration (i.e. defining a suitable parameter set on how to call what program on what data, and installing all the required tools).

It is itself written in Python, and relies heavily on the OCR-D core API. This is responsible for handling METS/PAGE, and providing the OCR-D CLI.

Installation

Create and activate a virtual environment as usual.

To install Python dependencies:

make deps

Which is the equivalent of:

pip install -r requirements.txt

To install this module, then do:

make install

Which is the equivalent of:

pip install .

Usage

OCR-D processor interface ocrd-preprocess-image

To be used with PAGE-XML documents in an OCR-D annotation workflow.

Usage: ocrd-preprocess-image [OPTIONS]

  Convert or enhance images

Options:
  -V, --version                   Show version
  -l, --log-level [OFF|ERROR|WARN|INFO|DEBUG|TRACE]
                                  Log level
  -J, --dump-json                 Dump tool description as JSON and exit
  -p, --parameter TEXT            Parameters, either JSON string or path 
                                  JSON file
  -g, --page-id TEXT              ID(s) of the pages to process
  -O, --output-file-grp TEXT      File group(s) used as output.
  -I, --input-file-grp TEXT       File group(s) used as input.
  -w, --working-dir TEXT          Working Directory
  -m, --mets TEXT                 METS to process
  -h, --help                      This help message

Parameters:
  "level-of-operation" [string - page] PAGE XML hierarchy level to operate on
    Possible values: ["page", "region", "line", "word", "glyph"]
  "input_feature_selector" [string - ] comma-separated list of required image features
    (e.g. binarized,despeckled)
  "input_feature_filter" [string - ] comma-separated list of forbidden image features
    (e.g. binarized,despeckled)
  "output_feature_added" [string - REQUIRED] image feature(s) to be added after this operation
    (if multiple, separate by comma)
  "input_mimetype" [string - image/png] File format to save input images to
    (tool's expected input)
    Possible values: ["image/bmp", "application/postscript", "image/gif", "image/jpeg",
      "image/jp2", "image/png", "image/x-portable-pixmap", "image/tiff"]
  "output_mimetype" [string - image/png] File format to load output images from
    (tool's expected output)
    Possible values: ["image/bmp", "application/postscript", "image/gif", "image/jpeg",
      "image/jp2", "image/png", "image/x-portable-pixmap", "image/tiff"]
  "command" [string - REQUIRED] shell command to operate on image files,
    with @INFILE as place-holder for the input file path,
    and @OUTFILE as place-holder for the output file path

TODO: add example recipes

• enhancement/conversion/denoising using
  • ImageMagick convert
  • GIMP script-fu
  • ...
• binarization using
  • scribo-cli
  • https://github.com/ajgallego/document-image-binarization
  • https://github.com/qurator-spk/sbb_binarization
  • https://github.com/masyagin1998/robin
  • ...
• text/non-text segmentation using
  • Olena scribo-cli
  • ...
• ...

OCR-D processor interface ocrd-skimage-normalize

To be used with PAGE-XML documents in an OCR-D annotation workflow.

Usage: ocrd-skimage-normalize [OPTIONS]

  Equalize contrast/exposure of images with Scikit-image

Options:
  -V, --version                   Show version
  -l, --log-level [OFF|ERROR|WARN|INFO|DEBUG|TRACE]
                                  Log level
  -J, --dump-json                 Dump tool description as JSON and exit
  -p, --parameter TEXT            Parameters, either JSON string or path 
                                  JSON file
  -g, --page-id TEXT              ID(s) of the pages to process
  -O, --output-file-grp TEXT      File group(s) used as output.
  -I, --input-file-grp TEXT       File group(s) used as input.
  -w, --working-dir TEXT          Working Directory
  -m, --mets TEXT                 METS to process
  -h, --help                      This help message

Parameters:
  "level-of-operation" [string - page] PAGE XML hierarchy level to
      operate on Possible values: ["page", "region", "line", "word",
      "glyph"]
  "dpi" [number - 0] pixel density in dots per inch (overrides any meta-
      data in the images); disabled when zero
  "method" [string - stretch] contrast-enhancing transformation to use
      Possible values: ["stretch", "adapthist"]

OCR-D processor interface ocrd-skimage-denoise-raw

To be used with PAGE-XML documents in an OCR-D annotation workflow.

Usage: ocrd-skimage-denoise-raw [OPTIONS]

  Denoise raw images with Scikit-image

Options:
  -V, --version                   Show version
  -l, --log-level [OFF|ERROR|WARN|INFO|DEBUG|TRACE]
                                  Log level
  -J, --dump-json                 Dump tool description as JSON and exit
  -p, --parameter TEXT            Parameters, either JSON string or path 
                                  JSON file
  -g, --page-id TEXT              ID(s) of the pages to process
  -O, --output-file-grp TEXT      File group(s) used as output.
  -I, --input-file-grp TEXT       File group(s) used as input.
  -w, --working-dir TEXT          Working Directory
  -m, --mets TEXT                 METS to process
  -h, --help                      This help message

Parameters:
  "level-of-operation" [string - page] PAGE XML hierarchy level to
      operate on Possible values: ["page", "region", "line", "word",
      "glyph"]
  "dpi" [number - 0] pixel density in dots per inch (overrides any meta-
      data in the images); disabled when zero
  "method" [string - VisuShrink] Wavelet filtering scheme to use
      Possible values: ["BayesShrink", "VisuShrink"]

OCR-D processor interface ocrd-skimage-binarize

To be used with PAGE-XML documents in an OCR-D annotation workflow.

Usage: ocrd-skimage-binarize [OPTIONS]

  Binarize images with Scikit-image

Options:
  -V, --version                   Show version
  -l, --log-level [OFF|ERROR|WARN|INFO|DEBUG|TRACE]
                                  Log level
  -J, --dump-json                 Dump tool description as JSON and exit
  -p, --parameter TEXT            Parameters, either JSON string or path 
                                  JSON file
  -g, --page-id TEXT              ID(s) of the pages to process
  -O, --output-file-grp TEXT      File group(s) used as output.
  -I, --input-file-grp TEXT       File group(s) used as input.
  -w, --working-dir TEXT          Working Directory
  -m, --mets TEXT                 METS to process
  -h, --help                      This help message

Parameters:
  "level-of-operation" [string - page] PAGE XML hierarchy level to
      operate on Possible values: ["page", "region", "line", "word",
      "glyph"]
  "dpi" [number - 0] pixel density in dots per inch (overrides any meta-
      data in the images); disabled when zero
  "method" [string - sauvola] Thresholding algorithm to use Possible
      values: ["sauvola", "niblack", "otsu", "gauss", "yen", "li"]
  "window_size" [number - 0] For Sauvola/Niblack/Gauss, the (odd) window
      size in pixels; when zero (default), set to DPI
  "k" [number - 0.34] For Sauvola/Niblack, formula parameter influencing
      the threshold bias; larger is lighter foreground

OCR-D processor interface ocrd-skimage-denoise

To be used with PAGE-XML documents in an OCR-D annotation workflow.

Usage: ocrd-skimage-denoise [OPTIONS]

  Denoise binarized images with Scikit-image

Options:
  -V, --version                   Show version
  -l, --log-level [OFF|ERROR|WARN|INFO|DEBUG|TRACE]
                                  Log level
  -J, --dump-json                 Dump tool description as JSON and exit
  -p, --parameter TEXT            Parameters, either JSON string or path 
                                  JSON file
  -g, --page-id TEXT              ID(s) of the pages to process
  -O, --output-file-grp TEXT      File group(s) used as output.
  -I, --input-file-grp TEXT       File group(s) used as input.
  -w, --working-dir TEXT          Working Directory
  -m, --mets TEXT                 METS to process
  -h, --help                      This help message

Parameters:
  "level-of-operation" [string - page] PAGE XML hierarchy level to
      operate on Possible values: ["page", "region", "line", "word",
      "glyph"]
  "dpi" [number - 0] pixel density in dots per inch (overrides any meta-
      data in the images); disabled when zero
  "maxsize" [number - 3] maximum component size of (bg hole or fg speck)
      noise in pt

Testing

none yet