MACHINE VISION CALIBRATION TARGETS AND METHODS OF DETERMINING THEIR LOCATION AND ORIENTATION IN AN IMAGE

A machine vision method analyzes a calibration target of the type having two or more regions, each having a "imageable characteristic," e.g., a different color, contrast, or brightness, from its neighboring region(s). Each region has at least two edges--referred to as "adjoining edges"--that are linear and that are directed toward and, optionally meet at, a reference point (e.g., the center of the target or some other location of interest). The method includes generating an image of the target, identifying in the image features corresponding to the adjoining edges, fitting lines to those edges, and determining the orientation and/or position of the target from those lines.