Arc Caliper Edge Filter Half-Width The filtering process smoothes out peaks in the magnitude curve that are caused by noise. Fil- ter Half-Width should be set to approximately the width of the edge, in pixels. An incorrect value can cause edges to be incorrectly detected. Projection Mode The two available projection modes are: l Annular - Annular projection is used to find edges that are aligned with the median annulus, such as arcs on concentric circles. The dotted arc in the following figure is the median annulus. ACEUser's Guide, 3.6.x, 18316-000 Rev A Page 368 Object Definition Custom Custom Sampling Step lets you set a sampling step value other than the default.
To select a cus- tom sampling step, Enable must be checked. Increasing the sampling step value reduces l the tool accuracy and decreases the exe- cution time. Reducing the sampling step can increase l the tool accuracy but will also increase the execution time.