18SIB03 BxDiff: New quantities for the measurement of appearance

• Research unit: METAS
• Project number: F-5116.30122

Key words (English)

Reflectance, transmittance, goniospectrophotometry, BRDF, BTDF, BSSRDF, polarisation, appearance, material

Short description (English)

Product appearance and visual branding are important drivers for consumer purchase decisions, as they underpin perceptions of ‘quality’ and ‘desirability’. The project aims to advance primary metrology in spectrophotometry to meet industrial needs for the quantitative measurement of appearance. This will be accomplished by i) defining new spectrophotometric quantities, ii) taking previously ignored corrections terms into account, and iii) developing new traceable spectrophotometric primary references which will provide new tools for quality control and more realistic solutions for virtual prototyping, and will benefit different industrial sectors e.g. automotive, paper, cosmetic and 3D-printing.

This is a joint research project carried out in the framework of the European Metrology Programme for Innovation and Research (EMPIR) (see:http://www.euramet.org/research-innovation/empir/). The EMPIR initiative is co-funded by the European Unions's Horizon 2020 research and innovation programme and the participating states. METAS is one of the project partners in the project.

Project aims (English)

The overall objective of the project is to define new traceable spectrophotometric references and advanced measurements that allow the characterisation of the visual appearance of surfaces.

The specific objectives of the project are:

1. To address advanced metrological issues related to measurement of the bidirectional reflectance distribution function (BRDF) in order to reduce by a factor 2 the measurement uncertainty to 0.1 % (k = 2) in the visible wavelength range. (WP1, WP5)
2. To establish a full metrological traceability of the BRDF from very small objects (micrometre scale) to regular objects (centimetre-scale). (WP1, WP4, WP5)
3. To develop primary reference facilities and reference samples (artefacts) for the measurement and dissemination of the bidirectional transmittance distribution function (BTDF) as a traceable quantity with a target uncertainty of 0.5 % (k = 2). (WP2, WP4, WP5)
4. To develop primary reference facilities and reference samples (artefacts) for the measurement and dissemination of the bidirectional scattering surface reflectance distribution function (BSSRDF) as a traceable quantity with a relative targeted uncertainty of 5 % (k = 2). (WP3, WP4, WP5)
5. To facilitate the take up of the technology and measurement infrastructure developed in the project by the measurement supply chain (NMIs, spectrophotometer manufacturers), standards developing organisations (CIE) and end users (e.g. automotive industry, video game developers, healthcare sector, visual arts sector, cosmetics, architectural materials manufacturers).