| 1 | <?xml version="1.0" encoding="UTF-8" standalone="no"?>
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| 2 | <!--
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| 3 | (XML comments only allowed after xml processor instruction.)
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| 4 |
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| 5 | https://opensourceconnections.com/blog/2019/11/26/tika-and-tesseract-outside-of-solr/
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| 6 | which links to their sample tika-config.xml (copied below) which configures the PDF and OCR Parsers to behave just as the old PDFParser.props and OCR Parser properties files did.
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| 7 |
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| 8 | - new way of one tika-config.xml: https://github.com/o19s/pdf-discovery-demo/blob/crazy_tika_tesseract_inside_of_solr/ocr/tika-config.xml
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| 9 | - old way of 2 props files: https://github.com/o19s/pdf-discovery-demo/tree/6f5b37305dd863a73af4617db64cbe853c5ecd2a/ocr/tika-properties/org/apache/tika/parser
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| 10 |
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| 11 | https://tika.apache.org/1.16/configuring.html
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| 12 | https://issues.apache.org/jira/browse/TIKA-2624
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| 13 | -->
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| 14 | <properties>
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| 15 | <parsers>
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| 16 | <parser class="org.apache.tika.parser.DefaultParser">
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| 17 | <parser-exclude class="org.apache.tika.parser.ocr.TesseractOCRParser"/>
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| 18 | <parser-exclude class="org.apache.tika.parser.pdf.PDFParser"/>
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| 19 | </parser>
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| 20 | <parser class="org.apache.tika.parser.ocr.TesseractOCRParser">
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| 21 | <params>
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| 22 | <!-- Setting the following 2 params is unnecessary, since sourcing Greenstone puts the Tesseract binary
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| 23 | on the path AND also sets the TESSDATA_PREFIX env var needed by Tesseract -->
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| 24 | <!--
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| 25 | <param name="tesseractPath" type="string">/path/to/GS3/gs2build/ext/tesseract/linux/bin</param>
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| 26 | <param name="tessdataPath" type="string">/path/to/GS3/gs2build/ext/tesseract/linux/tessdata</param>
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| 27 | -->
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| 28 |
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| 29 | <!-- IMPORTANT!! -->
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| 30 | <param name="outputType" type="string">hocr</param><!-- Choose one of: hocr, txt -->
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| 31 | <!-- hocr is preferred as Tesseract produces nicely formatted html that better reflects
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| 32 | the placement of the original text in the scanned page. (Can compare running with horc vs txt)
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| 33 |
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| 34 | However, initially, the above value had to be fixed as "txt", as outputType value = hocr prevented
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| 35 | Tika+Tesseract from OCR-ing pdfs (no OCR output).
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| 36 | Until $GEXT_INSTALLED/tessdata/configs/hocr (tesseract config file) was created containing specific
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| 37 | property values in point 2b below.
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| 38 |
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| 39 | To get Tika to work with Tesseract to OCR pages of a scanned PDF:
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| 40 | 1. always pass in this file as __config=/path/to/tika-config.xml to tika-app-*.jar cmd,
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| 41 | 2. AND do one of the following:
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| 42 | a. Set the above outputType param to "txt" so Tesseract produces the OCR in .txt format, and things should work,
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| 43 | b. OR if you want the OCR generated by Tesseract to be in hocr (html ocr) format, then set the outputType above
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| 44 | to "hocr" AND ensure a config file also called hocr exists in $TESSDATA_PREFIX/configs containing the following
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| 45 | (taken from
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| 46 | https://github.com/tesseract-ocr/tessconfigs/blob/3decf1c8252ba6dbeef0bf908f4b0aab7f18d113/configs/hocr):
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| 47 | tessedit_create_hocr 1
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| 48 | hocr_font_info 0
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| 49 |
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| 50 | More information about tesseract config options by running:
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| 51 | tesseract __print-parameters
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| 52 | -->
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| 53 | <param name="language" type="string">eng</param>
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| 54 | <param name="pageSegMode" type="string">1</param>
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| 55 | </params>
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| 56 | </parser>
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| 57 | <parser class="org.apache.tika.parser.pdf.PDFParser">
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| 58 | <params>
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| 59 | <param name="ocrStrategy" type="string">ocr_and_text</param>
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| 60 | </params>
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| 61 | </parser>
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| 62 |
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| 63 | </parsers>
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| 64 | </properties>
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