CIE x029:2006

12-13 June 2006, Braunschweig, Germany

In 2001 CIE has organized its first symposium on the evaluation of uncertainty in measurements. This follow-up conference held at the Physikalisch-Technische Bundesanstalt (PTB) Braunschweig, Germany summarized the latest results and trends in this topic, particularly the evaluation of uncertainties associated to values of photometric and radiometric quantities and developments related to methods for the assessment of uncertainties of quantities which are derived from spectral measurements.

The symposium was split into two main parts: tutorial and workshop. The tutorial covered fundamentals for uncertainty evaluation, modelling of measurements i.e. modules and measurement equations, combinations of modules, uncertainties of calculated quantities resulting from spectral measurements, uncertainty calculations in key comparisons and measurement uncertainty evaluation based on the propagation of distributions using Monte-Carlo simulation. The 1993 ISO publication “Guide to the expression of uncertainties in measurement” (GUM) is devoted to mainly linear models, the advantage of the Monte-Carlo method is that non-linear models and models with more than one output quantity can be handled. A separate lecture introduced the work of CIE TC 2-43 Determination of measurement uncertainties in photometry.

A great part of the contributed papers dealt with the analysis of spectral measurements. Ways to determine the correlation between the different spectral responsivities together with the calculation of the photometric responsivity were presented. The linear model and the Monte-Carlo simulation was compared and the additional possibilities, like the determination of the correlation matrix, of the Monte- Carlo simulation was analysed. Two papers addressed the question of the uncertainty of the average LED intensity. Further papers were read on industrial applications, scale realization, monochromator bandwidth correction, etc.