Summary

Project description

JRP Number: 23IND14

JRP Title: Multidimensional optical diffusion for the measurement of appearance

Start date: 01 June 2024

Duration: 36 months

Coordinating Organisation: CNAM, France

JRP-Coordinator: Gaël Obein

Publishable summary

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Planned work and objectives

The overall objective of the project is to provide industrial-level tools for capturing, reproducing and monitoring the visual appearance of real or virtual objects.

The specific objectives of the project are:

  1. To develop and characterise image-based goniospectrophotometers, including simplified version of these, and to use these to perform the traceable measurement of optical properties (e.g., BRDF, BTDF, BSSRDF) of actual manufactured surfaces e.g., anisotropic surfaces, non-flat surfaces, functional surfaces and translucent materials with target measurement uncertainties below 0.5 % for BRDF and BTDF, and around 2 % for BSSRDF for full goniospectrophotometers. The target uncertainties for simplified goniospectrophotometers are below 2 % for BRDF and BTDF and 4 % for BSSRDF.
  2. To model complex scattering quantities (e.g., BRDF, BTDF, BSSRDF) of industrial surfaces to define quantifying tools for the digitalisation and reproduction of the appearance of materials, including thresholding, sampling strategy, and interpolation models, and comparison metrics.
  3. To develop measurement scales for translucency and mattness. This includes the definition of physical quantities (e.g., BRDF and BSSRDF) which correlate with the visual sensation and the proposal of protocols for their measurement with a target uncertainty of 5 %.
  4. To tackle metrological issues in the field of bidirectional spectrophotometry that limit the knowledge and the uncertainties on spectrophotometric quantities, i.e., sphere-based quantities, transmittance of thick samples, multiscale traceability, effective refractive index, specular gloss index.
  5. To facilitate the take up of the technology and measurement infrastructure developed in the project by the EMN Advanced Manufacturing, measurement supply chain (NMIs, instrument manufacturers), standards developing organisations (ISO, CIE), and end users (e.g., automotive industry, video game developers, healthcare sector, visual arts sector, glass manufacturers).