Caliper Concepts

The Caliper step computes the minimum or maximum distance between two edges of an object enclosed in a region of interest. The region of interest contains a number of search lines along which the step searches for sharp transitions in pixel intensities. A sharp transition typically characterizes the edge of an object in the image.

The step locates an edge based on its edge strength. You can study the Edge Strength Profile to determine the edge strengths in the region of interest. A peak in the profile indicates that an edge is present at that position in the region of interest. The strength of that edge is given by the amplitude of the peak.

The step searches for two edge points along each search line and computes the distance between the two detected edge points. The step returns the minimum or maximum distance measurement of all the search lines as the caliper measurement.