Binarize with Olena/scribo
make deps-ubuntu
...will try to install the required packages on Ubuntu.
make build-olena
...will download, patch and build Olena/scribo from source, and install locally (in VIRTUAL_ENV or in CWD/local).
make install
...will do that, but additionally install ocrd-binarize-olena (the OCR-D wrapper).
make test
...will clone the assets repository from Github, make a workspace copy, and run checksum tests for binarization on them.
This package has the following user interfaces:
Converts images in any format.
Usage: scribo-cli COMMAND [ARGS]
List of available COMMAND options:
Full Toolchains
---------------
* On documents
doc-ppc Common preprocessing before looking for text.
doc-ocr Find and recognize text. Output: the actual text
and its location.
doc-dia Analyse the document structure and extract the
text. Output: an XML file with region and text
information.
* On pictures
pic-loc Try to localize text if there's any.
pic-ocr Localize and try to recognize text.
Tools
-----
* xml2doc Convert the XML results of document toolchains
into user documents (HTML, PDF...).
Algorithms
----------
* Binarization
otsu Otsu's (1979) global thresholding algorithm.
niblack Niblack's (1985) local thresholding algorithm.
sauvola Sauvola and Pietikainen's (2000) local/adpative algorithm.
kim Kim's (2004) algorithm.
wolf Wolf and Jolion's (2004) algorithm.
sauvola-ms Lazzara's (2013) multi-scale Sauvola algorithm.
sauvola-ms-fg Extract foreground objects and run multi-scale
Sauvola's algorithm.
sauvola-ms-split Run multi-scale Sauvola's algorithm on each color
component and merge results.
singh Singh's (2014) algorithm.
Other
-----
version Show version and exit
help Show this message and exit
For command arguments, see 'scribo-cli COMMAND --help' for more information
on each specific COMMAND.
For example:
scribo-cli sauvola-ms path/to/input.tif path/to/output.png --enable-negate-outputOCR-D processor interface ocrd-olena-binarize
To be used with PageXML documents in an OCR-D annotation workflow. Input could be any valid workspace with source images available. Currently covers the Page hierarchy level only. Uses either (the last) AlternativeImage, if any, or imageFilename, otherwise. Adds an AlternativeImage with the result of binarization for every page.
"ocrd-olena-binarize": {
"executable": "ocrd-olena-binarize",
"description": "OLENA's binarization algos for OCR-D (on page-level)",
"categories": [
"Image preprocessing"
],
"steps": [
"preprocessing/optimization/binarization"
],
"input_file_grp": [
"OCR-D-SEG-BLOCK",
"OCR-D-SEG-LINE",
"OCR-D-SEG-WORD",
"OCR-D-IMG"
],
"output_file_grp": [
"OCR-D-SEG-BLOCK",
"OCR-D-SEG-LINE",
"OCR-D-SEG-WORD"
],
"parameters": {
"impl": {
"description": "The name of the actual binarization algorithm",
"type": "string",
"required": true,
"enum": ["sauvola", "sauvola-ms", "sauvola-ms-fg", "sauvola-ms-split", "kim", "wolf", "niblack", "singh", "otsu"]
},
"win-size": {
"description": "Window size",
"type": "number",
"format": "integer",
"default": 101
},
"k": {
"description": "Sauvola's formulae parameter (foreground weight decreases with k); for Multiscale, multiplied to yield default 0.2/0.3/0.5; for Singh, multiplied to yield default 0.06; for Niblack, multiplied to yield default -0.2; for Wolf/Kim, used directly; for Otsu, does not apply",
"format": "float",
"type": "number",
"default": 0.34
}
}
}Copyright 2018-2020 Project OCR-D
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.