org.imixs.archive.ocr

Class OCRService

java.lang.Object

org.imixs.archive.ocr.OCRService

public class OCRService
extends Object

The OCRService extracts the textual information from document attachments of a workitem.

The text information is stored in the $file attribute 'text'.

For PDF files with textual content the PDFBox api is used. In other cases, the method sends the content via a Rest API to the tika server for OCR processing. The environment variable OCR_PDF_MODE defines how PDF files will be scanned. Possible values are TEXT_ONLY | OCR_ONLY | TEXT_AND_OCR (default)

For OCR processing the service expects a valid Rest API end-point defined by the Environment Parameter 'TIKA_SERVICE_ENDPONT'. If the TIKA_SERVICE_ENDPONT is not set, then the service will be skipped.

The environment parameter 'TIKA_SERVICE_MODE' must be set to 'auto' to enable the service.

See also the project: https://github.com/imixs/imixs-docker/tree/master/tika

Version:

1.1

Author:

rsoika

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_ENCODING
static String	ENV_OCR_PDF_MODE
static String	ENV_OCR_SERVICE_ENDPOINT
static String	ENV_OCR_SERVICE_MODE
static String	FILE_ATTRIBUTE_TEXT
static String	PDF_MODE_OCR_ONLY
static String	PDF_MODE_TEXT_AND_OCR
static String	PDF_MODE_TEXT_ONLY
static String	PLUGIN_ERROR

Constructor Summary

Constructors

Constructor and Description
OCRService()

Method Summary

Modifier and Type	Method and Description
String	doORCProcessing(org.imixs.workflow.FileData fileData, List<String> options) This method sends the content of a document to the Tika Rest API for OCR processing.
String	doPDFTextExtraction(org.imixs.workflow.FileData fileData) This method extracts the text from the given content of an PDF file.
void	extractText(org.imixs.workflow.ItemCollection workitem, org.imixs.workflow.ItemCollection snapshot) Extracts the textual information from document attachments.
void	extractText(org.imixs.workflow.ItemCollection workitem, org.imixs.workflow.ItemCollection snapshot, String pdf_mode, List<String> options) Extracts the textual information from document attachments.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FILE_ATTRIBUTE_TEXT

public static final String FILE_ATTRIBUTE_TEXT

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Constant Field Values

DEFAULT_ENCODING

public static final String DEFAULT_ENCODING

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Constant Field Values

PLUGIN_ERROR

public static final String PLUGIN_ERROR

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Constant Field Values

ENV_OCR_SERVICE_ENDPOINT

public static final String ENV_OCR_SERVICE_ENDPOINT

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Constant Field Values

ENV_OCR_SERVICE_MODE

public static final String ENV_OCR_SERVICE_MODE

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Constant Field Values

ENV_OCR_PDF_MODE

public static final String ENV_OCR_PDF_MODE

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Constant Field Values

PDF_MODE_TEXT_ONLY

public static final String PDF_MODE_TEXT_ONLY

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Constant Field Values

PDF_MODE_OCR_ONLY

public static final String PDF_MODE_OCR_ONLY

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Constant Field Values

PDF_MODE_TEXT_AND_OCR

public static final String PDF_MODE_TEXT_AND_OCR

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Constant Field Values

Constructor Detail

OCRService

public OCRService()

Method Detail

extractText

public void extractText(org.imixs.workflow.ItemCollection workitem,
                        org.imixs.workflow.ItemCollection snapshot)
                 throws org.imixs.workflow.exceptions.PluginException

Extracts the textual information from document attachments.

The method extracts the textual content for each new document of a given workitem. For PDF files with textual content the method calls the method 'extractTextFromPDF' using the PDFBox api. In other cases, the method sends the content via a Rest API to the tika server for OCR processing.

The result is stored into the fileData attribute 'text'

Parameters:

workitem -

Throws:

org.imixs.workflow.exceptions.PluginException

extractText

public void extractText(org.imixs.workflow.ItemCollection workitem,
                        org.imixs.workflow.ItemCollection snapshot,
                        String pdf_mode,
                        List<String> options)
                 throws org.imixs.workflow.exceptions.PluginException

Extracts the textual information from document attachments.

The method extracts the textual content for each new file attachment of a given workitem. The text information is stored in the $file attribute 'text'.

For PDF files with textual content the method calls the method 'extractTextFromPDF' using the PDFBox api. In other cases, the method sends the content via a Rest API to the tika server for OCR processing.

The method also extracts files already stored in a snapshot workitem. In this case the method tests if the $file attribute 'text' already exists.

Parameters:

workitem - - workitem with file attachments

pdf_mode - - TEXT_ONLY, OCR_ONLY, TEXT_AND_OCR

options - - optional tika header params

Throws:

org.imixs.workflow.exceptions.PluginException

doORCProcessing

public String doORCProcessing(org.imixs.workflow.FileData fileData,
                              List<String> options)
                       throws IOException

This method sends the content of a document to the Tika Rest API for OCR processing.

In case the contentType is PDF then the following tika specific header is added:

X-Tika-PDFOcrStrategy: ocr_only

Parameters:

fileData - - file content and metadata

Returns:

text content

Throws:

IOException

doPDFTextExtraction

public String doPDFTextExtraction(org.imixs.workflow.FileData fileData)

This method extracts the text from the given content of an PDF file. In case the pdf file does not contains text the pdf can be forwarded to the tika service for OCR scanning. In this case we append the header attribute X-Tika-PDFOcrStrategy=ocr_only.

Extracting text is one of the main features of the PDF box library. You can extract text using the getText() method of the PDFTextStripper class. This class extracts all the text from the given PDF document.

Parameters:

content -

Returns: