Multidimensional reflectometry for industry

Short Name: xDReflect, Project Number: IND52
Red Sport Car on a HighWay

Measuring complex visual effects reliably


The European automotive industry has a turnover of 900 billion euro – nearly 7 % of the EU’s GDP – with highly competitive car manufacturers vying to attract customers with stunning visual effects. Similar effects are used in printing and cosmetics, where colour, texture, gloss and sparkle drive sales. These complex surface finishes include particles and flakes to produce unique effects that depend on lighting conditions.

 

Instrumentation for quantifying visual effects and complex surface finishes is replacing expert inspections, providing greater consistency and efficiency in product quality control. Robust measurement methods and well-characterised reference standards are needed to improve links between human perception of complex visual effects and measurements made using instrumentation.

 

The EMRP Project Multidimensional reflectometry for industry, increased the accuracy of Bidirectional Reflectance Distribution Function (BRDF) measurements, used to determine quantitatively how light interacts with surfaces, and developed standards and statistical models to match measurements to our perception of complex visual effects.

 

The project:

 

  • Increased the accuracy of BRDF measurements to a resolution comparable with that of the human eye, enabling accurate optical characterisation of complex surface finishes.
  • Developed a faster method to assess visual effects using BRDF by identifying significant measurement orientations and applying new data analysis, reducing the time and complexity of measurements without sacrificing accuracy.
  • Constructed light booths for testing samples’ sparkle, iridescence and gloss under different lighting conditions, augmenting the understanding of human visual perception. This has the potential to increase the use of instrumentation in quality assurance measurements.
  • Developed a method and reference materials for measuring sparkle as a first step towards measurement standardisation and a future international documentary standard for sparkle effects.
  • Developed new approaches for the evaluation of measurement uncertainties in CIELAB colour space. The CIELAB colour space mathematically and uniquely describes all perceivable colours.

 

This project has increased the accuracy of instrument measurements for complex surface finishes and developed better statistical models and simulations to improve links between measurements results and our perception of complex optical effects. Project collaboration has created a unified European approach to measuring complex surface effects where each institute brings its own ethos and expertise, avoiding duplication and competition. New reference materials now provide increased SI traceability. Optical measurement calibration capabilities have been extended as a result of this project, and now cover the spectrum from the infrared to the ultraviolet. These provide improved SI traceability for instruments used in climate change studies, as well as those used for characterising materials used in solar energy cells.

 

A follow on EMPIR project Bidirectional reflectance definitions (BiRD) is building on XDReflect developments and is investigating increased standardisation for BRDF, sparkle, and gloss measurements and data formats. This new project aims to further improve quality assurance for complex optical effects important for the highly competitive EU industries that generate large volumes of export sales.

Project website
Publications
Color characterization of coatings with diffraction pigments
2016

Journal of the Optical Society of America A

Comparación de las propiedades fotométricas y colorimétricas de diferentes cabinas de iluminación
2016

Resúmenes de las contribuciones. XI Reunión Nacional de Óptica

Convolution and deconvolution of bidirectional scatter distribution function data to enable inter-instrument comparison
2016

Proceedings of the 4th CIE Expert Symposium on Colour and Visual Appearance

Impact of Surface Curvature on Spectral BRDF of Effect Coatings
2016

Proceedings of 4th CIE Expert Symposium on Colour and Visual Appearance

Influencia del Tamaño de Pigmento en la Distancia de Detección del Sparkle
2016

Resumen de la Contribuciones. XI Reunión Nacional de Óptica

Multi-Angle Colour Characterization of Coatings with Diffraction Pigments
2016

Proceedings of 4th CIE Expert Symposium on Colour and Visual Appearance

Evaluación de la fórmula de diferencia de color AUDI2000: análisis del croma
2016

Resúmenes de las contribuciones. XI Reunión Nacional de Óptica

Measuring Color Differences in Gonioapparent Materials Used in the Automotive Industry'conference
2015

Proceedings of 23rd Congress of the International Commission for Optics

Goniometric and colorimetric properties of paints and varnish
2015

SPIE Proceedings Measuring, Modeling, and Reproducing Material Appearance 2015

Visibility of sparkle in metallic paints
2015

Journal of the Optical Society of America A, Optics, Image Science and Vision.

Measuring and specifying goniochromatic colors
2015

Proceedings of 23rd Congress of the International Commission for Optics

Color gamut of a typical display for the color reproduction of effect coatings
2015

Proceedings of 23rd Congress of the International Commission for Optics

How to efficiently characterize special effect coatings
2015

Journal of the Optical Society of America A

Design of the MSc degree in Colour Technology for the Automotive Sector
2014

Conference Proceedings of the 13th International Science-to-Business Marketing Conference on Cross Organizational Value Creation

Statistical Analysis of BRDF Data for Computer Graphics and Metrology
2014

Lecture Notes in Engineering and Computer Science: Proceedings of the World Congress on Engineering and Computer Science 2014

Rapid determination of the photometric bidirectional scatter distribution function by use of a near field goniophotometer
2014

PROCEEDINGS OF SPIE VOLUME 9018: Measuring, Modeling, and Reproducing Material Appearance

Color representation and interpretation of special effect coatings
2014

Journal of the Optical Society of America A

Other Participants
Callaghan Innovation (New Zealand)