CIE x029:2006

In 2001 CIE has organized its first symposium on the evaluation of uncertainty inmeasurements. This follow-up conference held at the Physikalisch-TechnischeBundesanstalt (PTB) Braunschweig, Germany summarized the latest results andtrends in this topic, particularly the evaluation of uncertainties associated to values ofphotometric and radiometric quantities and developments related to methods for theassessment of uncertainties of quantities which are derived from spectralmeasurements.

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

A great part of the contributed papers dealt with the analysis of spectralmeasurements. Ways to determine the correlation between the different spectralresponsivities together with the calculation of the photometric responsivity werepresented. The linear model and the Monte-Carlo simulation was compared and theadditional possibilities, like the determination of the correlation matrix, of the Monte-Carlo simulation was analysed. Two papers addressed the question of theuncertainty of the average LED intensity. Further papers were read on industrialapplications, scale realization, monochromator bandwidth correction, etc.