2023:Read Zone (Value Extractor)
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This article is a work-in-progress or created as a placeholder for testing purposes. This article is subject to change and/or expansion. It may be incomplete, inaccurate, or stop abruptly. This tag will be removed upon draft completion. |
The Read Zone extractor allows you to extract text data in a rectangular region (called a "extraction zone" or just "zone") on a document. This can be a fixed zone, extracting text from the same location on a document, or a zone relative to an extracted text anchor or shape location on the document.
About
Read Zone is useful for extracting data from highly structured documents. If a document's structure is fixed, it's going to have the same fields in the same physical location from one document to the next. The Closing Disclosure forms we've been looking at in this article are themselves fairly fixed. For example, the "Loan Amount" listed on the first page is more or less in the same spot for every single Closing Disclosure. The dollar amount itself may change, but there's only so much room that amount can take up on the document.
If you can draw a rectangle around the value you want to extract, and the value falls within the boundaries of that rectangle for every single document, extraction may be as simple as just extracting the text in the rectangle's location. This is referred to as "zonal extraction". You draw a zone where the value exists on the page and return the text data falling in the zone.
Read Zone has a few different options for where the box is placed using the Location property. This can be one of four options:
- Fixed Region - This option is the simplest to set up. As the name implies, the extraction zone will be fixed on the page. It will stay in the same coordinates for every document. All you need to do is draw the box where you want to extract data.
- Relative Region - Instead of setting the extraction zone in a fixed location for every document, the Relative Region mode will anchor the zone to a text label on the document. The extraction zone's position will change relative to the label's position on the document, but will still have the same drawn dimensions.
- This option is useful to overcome issues arising during scanning printed documents. Slight variations can occur as to where a value is when printing or scanning a document, even for very structured documents. This can cause problems when drawing a single fixed region for the extraction zone. However, if you can anchor the zone off an extractable text value, the zone's position will shift according to that anchor's position.
- Text Region - The Text Region option creates an extraction zone using the logical boundaries of an extraction result. This can return all the text falling within the boundaries of the rectangle around the extractor's result.
- This can also be configured to provide results in a similar way the Relative Region option does, using text anchors located by an extractor to position the extraction zone's location. This means both methods can be used to position the zone relative to a point from document to document. The main difference is in how the zone is drawn.
- Shape Region - The Shape Region option is extremely similar to the Text Region option. However, instead of using text to anchor the extraction zone, it uses a shape detected from a Shape Detection or Shape Removal IP Command.
- This is the least common method used.
The Read Zone extractor can optionally re-process the text data with an OCR Profile. This can be used to perform custom OCR on the extracted text.
The text in the zone can also be itself extracted by a Value Extractor. This allows you to break up the document into a smaller portion and run an extractor on just the zone instead of the full document. Essentially, you use the Read Zone extractor to create a smaller data instance (from the larger document data instance) and use its Value Extractor property to return data from the smaller data instance.
How To
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In this example, a Value Reader is configured to return the "Loan Amount" value as described on the first page of a Closing Disclosure form, using the Read Zone Extractor Type.
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