White Gap hypothesis

Properties of a White Gap hypothesis in an Extraction Rules activity — Orientation, Histogram maximum, White Gap threshold, and search-among object types.

Hypotheses for White Gap elements are formulated by creating object histograms.

By default, a white gap is looked for among objects of the Raw Object type. To try and detect a white gap among other types of objects (e.g. separators), you need to specify an appropriate search condition in the additional search area properties for the White Gap element (Code Editor panel, Search Conditions section). For example, if you need to find a white gap in a region that can contain any type of object, use the expression Type: PictureObject + SeparatorObject + AnyText + PunctuationMark + CheckMarkObject;.

White Gap hypothesis properties

A formulated White Gap hypothesis has the following type-specific properties (in addition to the general ones):

Property	Description
Orientation	Specifies the orientation of the detected white gap.
Histogram maximum in search area	Specifies the maximum histogram value in the search area.
White Gap threshold	Specifies the calculated threshold for the histogram, over which the white gap will no longer be considered to be detected.
Histogram maximum within hypothesis	Specifies the maximum histogram value within the white gap hypothesis region.