Document Analysis

What is Document Analysis

The Document Analysis step is conducted to specify areas with the 'to-be-extracted' information and receive important inforation for the later Document Export step.

Within the Document Analysis step, the logical structure of the document has to be be analyzed and defined. For example:

  • What is the logical structure of the document?
  • Where are text blocks, paragraphs, lines?
  • Is there a table that should be reconstructed?
  • Are there any “images” on the page(s)?
  • Are there any barcodes to read?

ABBYY technology contains several variants of Document Layout Analysis:

Automatic Document Analysis

The Document Analysis (DA) searches and “finds” zones for recognition on the document images.

How it works:

  • The Document Analysis algorithms detect different elementary objects on the image, e.g.
    • words or parts of words
    • separators
    • connected components
    • color gradients, inverted text areas
    • …etc.
  • In the next step, based on this information, hypotheses for these blocks are formed and checked:
    • What is type of the block?
    • Where are the borders of the block?
    • What type of the document layout could it be (magazine, newspaper, book page) ?

In the following screenshot, the detected layout elements are displayed on the left-hand side (text, image and table blocks). These elements were precisely reconstructed in the processed document - the exported documents on hte right-hand side.

 

A thorough document analysis is even more important for documents with complex layouts multi-column magazine pages. The following screnshot shows the properly identified layout elements on the left-hand side as well as the resulting page with precisely reconstructed columns. 

Intelligent Document Analysis detecting columns:

 

Without the intelligent layout analysis, ony one large text block would be identified which would make the column reconstruction impossible and the resulting document would not be readable and therefor not usable for a human.

No detection of columns:

ABBYY Document/Layout Analysis Modes

Automatic Document Analysis in the SDKs can work in the different modes available in the OCR-SDKs:

  • Full layout analysis – Text, images, tables and barcodes are detected - see samples above.
  • Index mode - tries to find as much text on the image - even if they are embedded in images
  • Mode for Invoices and documents with complex tables
  • Barcode mode - ignores text and images, it only looks for barcodes
  • Lines mode - only returns the text in lines, even in a multi-column document

It is as well possible to use ABBYY SDK without applying the built-in document layout analysis. The developer can create own blocks/recognition areas by setting the co-ordinates manually. This is a comon way when specific data should be extracted and the position of this data is known (Field-Level-OCR - Zonal OCR)

 

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