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The Extraction Rules activity is a tree-like structure consisting of elements used to search for data fields. The search elements tree and the field structure will be displayed to the right of the document image, in the Search Elements and Fields tabs. AD_Semistructured_Structure_ElementsFields Using Search Elements, you can find various text and non-text objects on the document image. You can use elements that have already been detected as anchors for specifying the location of other elements and fields. Elements corresponding to skill fields are created automatically when a field is enabled in an Extraction Rules activity. They can also be modified, moved in the Search Elements tree, and deleted. Once the required elements have been created and set up, create links between elements and the searched fields (for more information, see Field Properties). A Cartesian coordinate system is used to specify the location of objects on the image and the distance between them. The system origin (0, 0) is located exactly in the upper left corner of the image. The horizontal coordinate value increases as you move from left to right, and the vertical coordinate value increases as you move from top to bottom.

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Exporting an Extraction Rules activity

If you want to reuse an Extraction Rules activity in another skill, you can export it as a JSON file. To export an Extraction Rules activity as JSON file:
  1. In the Activity Editor, click the more icon and then click Export….
  2. In the dialog box that opens, choose a folder where you want to save the Extraction Rules activity as a JSON file.

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Units used to measure objects

In the Extraction Rules Activity Editor, various units of measurement can be used: millimeters, centimeters, inches, dots (1/300th of an inch), points (1/72nd of an inch). The sizes of objects, intervals, etc. can be specified in the selected unit of measurement. The program converts all distances to dots and uses that particular unit of measurement when matching the Extraction Rules activity, hence the measurement precision of all values is equal to 1 dot. The unit of measurement can be selected in the menu in the Toolbar (Options - Units section). Changing the unit of measurement will cause all specified sizes and distances to be converted to the specified unit. The current unit of measurement used in the program is displayed in the bottom pane: UnitsOfMeasurement