A method for the selection of algorithms for form characterization of nominally spherical surfaces

This paper presents a method for the selection of algorithms for the form c haracterization of nominally spherical surfaces. The form characterization is applied to discrete data obtained from a three-dimensional (3-D) high-pr ecision measurement system. In this paper, five sphere-fitting algorithms a re outlined and compared. The fitting algorithms under investigation are: l inear and nonlinear least-squares sphere fit, minimum zone sphere fit, four -point sphere fit, and sphere fit by error curve analysis. A method for sel ection of the best-fit algorithm, based on a spectral analysis of the surfa ce irregularity is suggested and applied to the surface measurement of worn electrical switching contacts. (C) 2000 Elsevier Science Inc. All rights r eserved.