Detect Signature (Extractor Type)

⚠	This article was migrated from an older version and has not been updated for the current version of Grooper. This tag will be removed upon article review and update.

This article is about the current version of Grooper.

Note that some content may still need to be updated.

2025

2023

Detect Signature is an Extractor Type that cant detect if a handwritten signature is present on a document. It detects signatures within a specified rectangular region on a document page by measuring the "fill percentage" (what percentage of pixels are filled in the region).

You may download the ZIP(s) below and upload it into your own Grooper environment (version 2023). The first contains a Project with resources used in examples throughout this article. The second contains one or more Batches of sample documents.

About

Detect Signature is an Extractor Type specifically designed to detect if a signature is present or not. It's very similar to the Read Zone extractor in that you use one of the four Location options (Fixed Region, Relative Region, Shape Region or Text Region) to draw an extraction zone on a geographic region of the page.

However, rather than returning the OCR or native text data within the zone (as Read Zone does), an OMR-style extraction is performed. Think about a signature line. If you drew a box around where you expect someone to sign, nothing would be in the box if it was not signed. But regardless of the signature, some of the box would be filled in if it were.

The same basic concept applies for the Detect Signature extractor. Detect Signature determines this by a simple pixel count of the percentage of black pixels in the zone. Essentially, the extractor counts the number of black pixels in the extraction zone. If the number of black pixels falls above a certain percentage threshold, the extractor returns a value of "Signed" and if below it returns a value of "Not Signed".

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BE AWARE: Detect Signature's setup is similar to the Read Zone extractor in that it uses the same Location properties the Read Zone extractor uses to draw the an extraction zone.

This article presumes you are familiar with the Read Zone extractor and its setup.
If you are not familiar with Read Zone, you may find it helpful to review the Read Zone article prior to following the tutorial in this article.

How To

In this example, a Value Reader is configured to return whether or not the "Senior Cow Representative Signature" is present on this Application for Cow Ownership form, using Detect Signature.