MetaTool > Help > Extraction > Blank Detection

060-540 MetaTool Extraction – Blank Detection Rule

MetaTool’s Blank Detection rule makes it possible to detect the blank spaces on documents. You can then use the Digital Imprinter to place a stamp or variable text in the blank space using the CaptureBites Digital Imprinter.

For example, we want to place a stamp directly under the text and signatures on below legal documents.
The text can end anywhere on the last page of the last page of the document. On the left document, there are only a few lines on the last page of the document and the stamp needs to be imprinted much higher than on the right document.

We will use the Blank Detection rule to return the distance from the top to the place where the text and signatures end and use that distance in the Digital Imprinter settings to imprint the stamp correctly.

Original: Unmarked documents
The final result will look like this (notice how the stamp automatically moved with the bottom of the text):
End result: Marked documents

01 Blank Detection – Add Rule

Blank Detection is defined in the MetaTool Extract tab.

Press the Add button and select Zonal Extraction / Blank Detection to add the extraction rule.

The Blank Detection Setup window opens.

02 Blank Detection – Setup

Select the index field to hold the distance in cm or inch (switches automatically with the Windows regional settings) from the top of the page to the end of the text. In our example we have used an index field named “Stamp Position”.

Optionally enter a description.

03 – On page: sometimes the blank space you want to find on a document is on another page than page 1. With this option, you can exactly define on which page to look for the blank space. Select -1 for the last page.
04 – Noise level: increase the value to detect blank space containing background noise.
05 – Testing your settings: after the setup of the Blank Detection rule, press the Test button and you will see the processed value in cm (in inch in US). This value specifies the start of the blank space which is the vertical distance between the top of the page to the place where the text and signatures end.

So in this example case, the blank space on the 1st document starts at 7,72 cm (3,04 inch) from the top of the page.
The blank space on the 2nd document starts at 20,42 cm (8,04 inch) from the top of the page.

Result Processed Value 1st document
Result Processed Value 2nd document

06 Blank Detection – Using the Processed Value in the Digital Imprinter

To use the processed value and set up the custom stamp, install the CaptureBites Digital Imprinter.
Select the Digital Imprinter in the MetaTool Export tab and press the Setup button.

The Digital Imprinter Setup window opens. Select the Image tab and select the image of the stamp you want to use (Browse…).
Images can be PNG, JPG etc. But we recommend a transparent PNG so you can see through the image of the stamp.

07 – Location: here you can specify where you want the stamp to be placed relative to the margins (see next option).

In this case, select the Top right location.

08 – Margins: select the “Stamp Position” index value which was automatically calculated with the Blank Detection rule for the Top-margin. This will move the stamp in the blank zone automatically. The other margins are fixed values and are always the same.