Self-Calibration: Reversal, Redundancy, Error Separation and Absolute Testing
(W. Tyler Estler, National Institute of Standards and Technology, and Chris J. Evans, Zygo Corporation)

Over the years many techniques have been developed for accurate measurement of part features without reference to an externally calibrated artifact. This tutorial will present a partial survey of such methods for dimensional metrology, their ranges of applications, and their limits. A broad range of applications will be covered, including methods for flatness, squareness, straightness, level, probe ball calibration, and angle and linear scale calibration. The tutorial also attempts to distill the common features of the various methods in the hope that this may provide the basis, or inspiration, for the development of "new" reversals or aid the development of new combinations of techniques to address specific metrology problems. All techniques will be covered first at the conceptual, mechanistic level; then each will be treated with appropriate analytical tools. Most techniques require no more than simple algebra and trigonometry; a small percentage requires mathematical skills typical for graduate engineers.