Locator Contrast Polarity Contrast Polarity defines the polarity change in grey-level values between an object and its background. This polarity can be dark to light or light to dark. The reference polarity for an object is defined by its Model. Polarity is always defined with respect to the initial polarity in the image on which the Model was created. Normal polarity Searches only for object instances having the same object-to-background polar- ity as the Model. For example, if the model is a dark object on a light back- ground, the Locator searches only for dark objects on a light background.
Reverse Restricts the Locator to search only for objects having a object-to-background polarity that is inverse to that in the Model. For example, if the model is a dark object on a light background, the Locator searches only for light objects on a dark background. Contrast Polarity - Model, Normal, and Reverse Normal And Reverse Enables the Locator to search for all cases that present either Normal or Reverse polarity. This will not take into account cases where polarity is reversed at various locations along the edges of an object. Do Not Care Detects complete contrast reversal, as well as local contrast reversal, on ACEUser's Guide, 3.6.x, 18316-000 Rev A Page 564