Coordinate Measurement Data Analysis

Coordinate metrology generates important software issues. After measurement data are collected in the form of position vectors, the data analysis software must derive the necessary information from the set of points. Uncertainty is an important issue in this data analysis. When extreme fit approaches are employed for form error evaluation, the uncertainty is closely related to the sampling of measurement points. Those measurement points are a subset of the true surface and, consequently, the extreme fit result differs from the true value. In this paper, we investigate the functional relationship between such an extreme fit uncertainty and the sampling of measurement points. The important questions to be answered are: what parameters affect the functional relationship, and how can this scheme be applied to sampling of measurement points. An analytic and experimental approach are presented for a flatness example.