Configure OCR step and OCR providers

In Work.AI, the OCR step is available in two variations:

• No-code OCR step

• Legacy OCR Bridge step

The OCR and OCR Bridge steps let you process documents in a Business Process (BP) and pass optical character recognition (OCR) results to the next step, such as a Model or labelling Manual Task step.

Add no-code OCR step to Business Process

To add a no-code OCR step to a BP, follow the steps below:

1. In an existing BP, navigate to the Workflow tab.

   

2. In the step panel on the right, select Bot and click Models to open the list of available no-code steps.

3. Add the OCR step to the Workflow Designer canvas in one of the following ways:

   • Reuse an existing step. Drag an existing OCR step from the Bot panel on the right to the canvas. In this case, any changes you make to the step are applied across all BPs where the same step is included.

     

   • Reuse an existing step. Drag an existing OCR step from the Bot panel on the right to the canvas. In this case, any changes you make to the step are applied across all BPs where the same step is included.

4. Double-click the step on the canvas and set a name for the step in the Bot step display name field.

   

5. Navigate to the Input / Output tab of the OCR step to set up the input and output contracts. For details, see the guide.

6. Go back to the Design tab and configure the OCR step parameters.

7. Click Save to save the created OCR configuration.

tip

For an end-to-end tutorial on creating a BP with no-code OCR, Model, and Manual Task steps, see the guide.

Add legacy OCR Bridge step to Business Process

Alternatively, you can create the same BP using a legacy OCR Bridge step. The setup sequence for the step is similar to the one described above.

tip

For an end-to-end tutorial on creating a BP with no-code OCR, Model, and Manual Task steps, see the guide.

Configure OCR step

To configure an OCR step, double-click the step in the canvas to open the configuration window (if it is not open yet) and perform the following actions on the Design tab:

1. Set the OCR step input parameters.

2. Choose an OCR engine.

3. Set the OCR parameters corresponding to the chosen OCR engine.

Set step input parameters

Parameter	Code	Default value	Description
Document URL	document_url	original_document_url	Specify the URL of the document to be processed by OCR. Typically, the data comes from the BP input.
When the step fails	go_forward_on_failure	Complete the step and move to the next one with an error (yes)	Specify the action to be done if the failure result is received. If you choose Complete the step and move to the next one with an error (set the code value to yes) and the failure answer is received, the step is completed, and an error message is sent to the next step.
OCR type	ocr_type	Enriched	Select Standard or Enriched. In the latter case, you enable preparing the OCR output for a labelling Manual Task.
S3 bucket name	s3_bucket_name	doc-upload	Specify the S3 bucket to store the OCR output.
S3 folder name	s3_folder_name	empty	Specify the S3 folder to store the OCR output.
OCR engine	ocr_provider	ABBYY	Select an OCR provider: ABBYY Google Vision Azure AI Document Intelligence Paddle OCR
OCR parameters	ocr_parameters	See OCR JSON sample	See the OCR parameters.

Choose OCR provider

To configure an OCR provider, choose one from the OCR engine drop-down list and set the required paratemers. For details, read Set OCR parameters.

Work.AI supports the following OCR providers:

• ABBYY
• Azure AI Document Intelligence
• Google Vision
• Paddle OCR

info

• Responses from Azure AI Document Intelligence, Google Vision, and Paddle OCR are converted to the ABBYY output format.

• Azure AI Document Intelligence, Google Vision, and Paddle OCR are available only from the OCR step in the Control Tower user interface. ABBYY is available both from REST API and the OCR step.

For providers other than ABBYY, mind the following considerations:

• If you select Google Vision or Azure AI Document Intelligence, check that the default configuration includes the following parameters:

  • In the OCR type field, choose Enriched.

  • In the OCR parameters box, update the settings as follows:

    • exportFormat: xmlForCorrectedImage,xmlWithoutRecognitionVariants
    • writeRecognitionVariants: true
    • skipPreprocessing: false
    • storePreprocessedDoc: true
    • timeout: 60

    Note: if any of these settings are not configured as listed, OCR throws an exception.

    

• To use Google Vision or Azure AI Document Intelligence, set up additional Secrets Vault credentials.

• If you select Paddle OCR, follow the instructions in the official PaddleOCR documentation to configure the parameters.

  Note: The ocr_version parameter should be set to PP-OCRv5.

Set Secrets Vault credentials

The Work.AI platform does not manage Google secret keys and Azure credentials, so you must add them using one of the methods described below.

Method 1. New installation

As you install Work.AI, set the following properties in config.yml:

• ocr_google_key
• ocr_azure_password
• ocr_azure_endpoint

note

ocr_google_key must contain a Base64-encoded JSON Google key. Otherwise, escaping issues can occur in Ansible. If you pass the key as JSON or as separate properties, the private key can cause issues because it contains \n new lines and vault values with new lines.

Method 2. Existing installation

Set or create the same properties in config_overrides.yml in /opt/workfusion/wf_installer.

To override the parameters in the backup, run:

./install.sh install installer-backup -e @config_overrides.yml

To restart the OCR service with the parameters from config_overrides.yml, run:

./install.sh configure ocr -e @config_overrides.yml

If the steps above cause errors, make sure that the Ansible vault pass and key properties are set:

cd /opt/workfusion/wf_installer

export ANSIBLE_VAULT_PASS=$(cat config_overrides.yml | grep ansible_vault_password | cut -c 25- | tail -1)

export ANSIBLE_PRIVATE_KEY_FILE="id_rsa"

Set OCR parameters

The table below lists all available OCR parameters and their descriptions:

Parameter	Values	Description
exportFormat	xmlForCorrectedImage	Represents the OCR API export format. You can define multiple export formats using a comma as a separator: xml,xmlForCorrectedImage. For correct processing of a labelling MT, you cannot use more than three export formats.
	txt	It is the default export format.
	xml	Contains characters or words along with their location in the original document (coordinates or frames).
	xmlWithoutRecognitionVariants	The same as xml but does not contain character-related data.
	xmlForCorrectedImage	The same as xml, except the location is taken from a processed or adjusted document.
	pdfSearchable
	html
language	English German so on	Defines the default OCRed document language. You can also define multiple languages using a comma as a separator: English,German,Polish.
correctSkew	boolean	Detects the page skew and corrects it automatically.
correctOrientation	boolean	Detects the page orientation. If it differs from normal, the page is rotated automatically.
writeRecognitionVariants	boolean	For the xml and xmlForCorrectedImage formats, provides variants of characters or words that OCR considers a possible recognition result.
invertImage	boolean	Inverts images.
discardColorImage	boolean	Leaves only the black-and-white plane in a prepared image.
skipPreprocessing	boolean	Disables all preprocessing steps for a document. The default value is false. If you set to true, the convertTo and changeDPI parameters are disabled.
useOnlyCustomRegions	boolean	Skips the original analyzing stage and extracts information from custom regions only.
useDefaultPattern	boolean	If true, it requires applying the default pattern from the OCR application bundle.
profile	documentConversion	Converts documents into editable formats.
	textExtraction	Extracts text from documents.
	barcodeRecognition	Extracts barcodes.
removeGarbageSize	integer	Removes garbage, such as excess dots smaller than a specific size. The setting is optional, and the valid values are > 0 and -1.
lowResolutionMode	boolean	Improves the recognition of images with low resolution.
enhanceLocalContrast	boolean	Specifies whether the local contrast of an image should be increased.
convertTo	none	Automatically detects the file type and converts it to TIFF before processing. Accepts the PDF, PNG, JPG, JPEG formats.
changeDPI	integer valid range from 50 to 3200 null or 0 for disable	Specifies the resolution value, for example, changeDPI=300. The recommended resolution for a source image is 300 DPI for typical texts (10 pt or larger) and 400-600 DPI for texts in smaller fonts (9 pt or smaller).
version	V_2	ABBYY FRE 12
	V_1	ABBYY FRE 11
storePreprocessedDoc	boolean	Specifies whether preprocessed documents should be saved in the data storage.
textTypes	normal typewriter matrix ocrA ocrB e13b	Specifies the type of the text in the document. You can define several text types using a comma as a separator: normal,matrix.
timeout	integer	Sets the maximum allowed timeout in seconds for a single task execution by an OCR Worker. The timeout countdown starts when an OCR Worker begins executing a task. When the task execution exceeds the given timeout, the task is forcibly killed. If you do not set the value, the default value (0) is used, and your BP does not have time to process a task.

If native_pdf_processing is set to true, the skipPreprocessing and convertTo parameters are disabled. Such parameters as changeDPI and storePreprocessedDoc take effect only after you save pages of an input PDF.

troubleshooting

In case of issues with input data, see the Issues related to input data support guide.

OCR JSON sample

Below is a JSON sample with default values you can find in the OCR parameters field:

{
  "exportFormat": "xmlForCorrectedImage,xmlWithoutRecognitionVariants",
  "language": "English",
  "correctSkew": true,
  "correctOrientation": true,
  "writeRecognitionVariants": true,
  "invertImage": false,
  "discardColorImage": false,
  "skipPreprocessing": false,
  "useOnlyCustomRegions": false,
  "useDefaultPattern": false,
  "profile": "documentConversion",
  "removeGarbageSize": 0,
  "lowResolutionMode": false,
  "enhanceLocalContrast": false,
  "allowedRegionTypes": null,
  "changeDPI": 0,
  "version": "V_2",
  "storePreprocessedDoc": true,
  "textTypes": ["normal"],
  "timeout": 60
}

Review output

• OCR result: document processing results in the JSON format

  • Code: ocr_result

  • Example:

  {
      "originalDocument": "https://minio-host/doc-upload/1.pdf",
      "documents": {
          "xmlForCorrectedImage": "https://minio-host/doc-upload/bp-id/task-id/1- xmlForCorrectedImage.xml",
          "xmlWithoutRecognitionVariants": "https://minio-host/doc-upload/bp-id/task-id/1-xmlWithoutRecognitionVariants.xml"
      },
      "pageDetails": "https://minio-host/doc-upload/bp-id/task-id/preprocessed/links.json"
  }

• Task ID: the ID of an OCR task

  • Code: task_id
  • Example: 066416ed-20e8-4e96-9df1-7f7e133f1211

• Meta info JSON: extended info for the labelling Manual Task

  • Code: meta_info_json
  • Example:

  {
      "pages": "https://minio-host/doc-upload/bp-id/task-id/preprocessed/links.json",
      "ocrXmlUrl": "https://minio-host/doc-upload/bp-id/task-id/1-xmlWithoutRecognitionVariants.xml",
      "imageUrl": "https://minio-host/doc-upload/1.pdf"
  }

• Process time: record process time in milliseconds

  • Code: _sys_ocr_process_time
  • Example: 24053

See an output JSON sample for https://minio-host/doc-upload/bp-id/task-id/preprocessed/links.json below:

[
    {
        "imgUrl": "https://minio-host/doc-upload/bp-id/task-id/preprocessed/1.png",
        "charsUrl": "https://minio-host/doc-upload/bp-id/task-id/preprocessed/1.json",
        "height": 3300,
        "width": 2550,
        "charsCount": 2216
    }
]

tip

To set your Java Native Worker to work with the OCR step data, it is recommended to use the respective dependency from the WorkFusion's repository:

<groupId>com.workfusion.spa</groupId>
<artifactId>bridge-step-contracts</artifactId>

Using the library facilitates the implementation and reduces the time to production for such solutions.

Set up OCR REST configuration properties

note

The Azure, Google Vision, and Paddle OCR providers are available only from the OCR step in the Control Tower user interface. ABBYY is available both from REST API and the OCR step.

Property	Default value	Description
execution.bridge.task.queue	exec.<CT_HOST>.result.ocr	Name of the OCR step queue
execution.bridge.prefetch.count	100	Prefetch count of the OCR step queue
execution.bridge.thread.count	20	Count of threads for consuming messages of the OCR step queue