Arc Caliper Edge Pair Parameters There are two criteria that affect the choice of valid edges: Polarity and Edge Score Con- straints. Polarity Polarity corresponds to the change in light values, moving from left to right in the display, along the X-Axis in the region of interest. The caliper applies the Polarity constraint before applying edge-score Constraints. Polarity does not affect the edge score, but only edges that meet the selected Polarity are retained as valid edges, regardless of their scores. l Dark to Light will only accept edges occurring at transitions from a dark area to a light area.
l Light to Dark will only accept edges occurring at transitions from a light area to a dark area. l Either will accept any edge, regardless of its polarity. Edge Polarity Edge Score Constraints There are two types of constraints: Position and Magnitude. You can set the cal- iper to use only one constraint or both. The graphical Function Editor is provided for viewing and setting each type of constraint. l If only one constraint is selected, edges are scored based on the selected l If both constraints are selected, each constraint accounts for 50% of the constraint. edge score.
Magnitude Constraint The Magnitude constraint is based on edge values relative to the Magnitude ACEUser's Guide, 3.6.x, 18316-000 Rev A Page 363