Novel Method for Inline Estimation of Probing Uncertainty in Optical Measurement

Typically measuring points in optical coordinate metrology are considered equally at the subsequent fitting of geometric elements, for example circle. Thereby it is assumed that the related probing uncertainty does neither vary locally nor between different measuring objects. This paper outlines a novel approach for the determination of quality measures as a measure for the related probing uncertainty. The quality measures are based on the quantitative evaluation of the intensity characteristic at the edge, whose position is to be measured. Thereby five different criteria such as slope, width, form, noise and uniqueness of the edge are utilised. The overall quality measure is calculated as a weighted sum of the individual quality measures. The proposed quality measures have been applied at a number of different measuring objects. The experimental data prove the soundness of the new approach. The utilisation of the proposed quality measures results in a decrease of measuring uncertainty.