10.2

Edit

Tune OCR Business Process

A standard Workfusion OCR use case provides a set of Bot Configurations that may be re-used or extended to address custom OCR challenges.

OCR architecture

The UML diagram is as follows:

Usage example

     <var-def name="submitImage">
        <http url="${ocr_url}/submitImage" method="post" multipart="true">
            <http-param name="file" isfile="true">
                <http url="${original_document_url}" />
            </http-param>
        </http>
    </var-def>
      
    <var-def name="taskId">
        <xpath expression="string(//response/task/@id)">
            <var name="submitImage" />
        </xpath>
    </var-def>
  
      <script><![CDATA[
        //-------------------------------------------------------making processDocument url-------------------------------------------------------  
      .....
    ]]></script>
  
    <var-def name="processDocument">
        <http url="${processDocumentUrl.toString()}" method="get" />
    </var-def>

Metrics and licensing

Workfusion OCR capabilities are limited by the corresponding license. Every OCR license can be checked via Platform Monitor, or directly via URL (for RPA Express 2.0, license check url is http://localhost:15580/api/v1/cloud/activeLicense). Upon OCR license expiration Workfusion provides license upgrades.

Every OCR document processing request provides short metrics snippet to estimate the OCR load and predict the completion of the task.

<metrics averagePagesPerDoc="6.0" tasksInQueue="12" processedPages="260.0" timeInterval="300"/>

Client features comparison table


 OCR Plugin OCR REST
Execution Synchronous Asynchronous
Input Format PDF, TIFF, JPEG, PNG PDF, TIFF, JPEG, PNG
OCR Result Format TXT, XML, HTML, PDF TXT, XML, HTML, PDF
Usage

low age volume, good document quality,

no sla, OCR test

 Enterprise grade BP

Common parameters

Parameter Recommended Value Notes
Export Format xmlForCorrectedImage
Document Language
Language parameter must be supported by the license
Character Recognition Variance false
Allowed Region Type 
BT_Table,BT_Text,BT_Separator,BT_SeparatorGroup,BT_AutoAnalysis
Custom Region

Change DPI

Correct Orientation true
Correct Skew true
Invert Image

Discard Color Image

Remove Color Objects

Remove Color Object Types

caution

Bar Code recognition is not working with TOOD OCR, the page is empty with the Bar Code region specified. Use Standard OCR to get Barcodes working.

Optimization instructions

  1. Validate source image DPI. Recommended DPI for all source documents is 300-350. When resolution is 25% lower than recommended by WorkFusion, it is suggested to add image pre-processing parameter Change DPI or use ImageMagick to bump up the DPI to suggested level.
    1. When DPI is significantly lower, for example is within 72-110 DPI, increasing the DPI increases OCR recognition errors.
  2. It is suggested to use color documents within OCR process. A color image, since it has different colors presence, adds ability to remove RGB color channels prior to the processing, decreasing the document noise and providing a way to stabilize the image prior to applying gray-scale conversion.
  3. When looking at poor quality documents the only three pre-processing techniques proven to work within WorkFusion OCR Rest:
    • Adjusting contrast
    • Adjusting brightness
    • Inverting an image
  4. The OCR recognition result varies upon applying Allowed Region Type parameter values in a certain order. When setting array of two elements BT_Table, BT_Text as the value, the OCR result XML will have more OCR blocks as tables, than when the array has elements in reverse order BT_Text, BT_Table.
  5. See also Improve OCR Results for more improvements.
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