News

Two more courses in July and August follow the first event which was well-attended by stakeholders from industry and research

The project

EMPIR project Revision and extension of standards for test methods for LED lamps, luminaires and modules (19NRM02, RevStdLED) is developing metrology for the characterisation of light sources, especially those using LEDs (light emitting diodes).

To determine and characterise glare, as well as luminance distributions in general, imaging luminance measurement devices (ILMDs) are becoming more and more important. However, uncertainties associated with ILMDs are difficult to estimate as many corrections are applied by manufacturers, which, in most cases, depend on the application the ILMD is used for. In addition, cheaper solutions based on DSLR cameras are on the market promising accurate results and higher sensitivity to improper boundary conditions.

To demonstrate the impact of uncertainty-relevant boundary conditions when using ILMDs, the RevStdLED project held a two-day training session on the calibration and verification of ILMDs. This hands-on training was the first of three workshops (offered free of charge) dealing with practical issues for users and test houses regarding the handling of uncertainties of measurements. Roughly 30 participants from industry, test houses, National Metrology Institutes and universities were instructed by project partners how to perform measurements to characterise ILMDs. They also learned how the quality indices described in the CIE report “Characterization of Imaging Luminance Measurement Devices (ILMDs)” (CIE 244:2023) can be used to estimate the most important uncertainty contributions of a measurement.

Training contents of the workshop were:

• Fundamentals of ILMDs
• Overview of CIE 244:2010
• Adjustments by manufactures
• Fundamentals of luminance standards
• Internal model of evaluation
• Estimation of uncertainties
• Checklist on handling of ILMDs
• Dealing with temporal light modulation
• Uncertainty components (non-linearity, spatial characterization, size-of-source effect, dark signal, straylight, ambient temperature)
• Lab-based demonstrations on uncertainty components

In addition, the manufacturers of ILMDs involved in the project gave a "behind the scenes" insight regarding the investigations they have carried out on the camera systems.

All the information is processed and summarised in a Good Practice Guide on the calculation of uncertainties of integral quantities determined from correlated spectral input data for users, the outline of which has already been presented to the participants of the training. This guide will be made available by the partners of the consortium by the end of the project.

The next free of charge training sessions as part of the 19NRM02 RevStdLED project are:

Training session on uncertainty of correlated spectral data

Date:       24 July 2023

Venue:    Online

This workshop focuses on using measured spectral data to determine integral photometric or radiometric quantities. Although the measurement of spectral data typically provides correlated data sets, these correlations are typically ignored. A good practice guideline for dealing with such correlations when calculating the uncertainty is presented, which in particular contains an introduction to Monte Carlo methods.

Training session on the measurement of integral quantities

Date:       22 – 23 August 2023

Venue:    TÜBITAK, Turkey

This workshop provides hands-on training in the measurement and analysis of integral quantities. The focus is on the appropriate design of a measurement setup for photometric quantities and the development of the evaluation model to calculate the associated measurement uncertainty.

This EMPIR project is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States.

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