What is it about?

To characterize the optical diffuse transmission of a material, one needs to measure the so-called bidirectional transmittance distribution function (BTDF). In this paper, a bilateral scale comparison on the capability of performing BTDF measurement was reported for the first time at the European Union (EU) level. Good consistency was achieved between the results obtained from two newly developed BTDF reference setups and action points for their future improvement were identified.

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Why is it important?

Quantitative characterization of a material’s translucency, as a physical effect caused by the diffuse transmission of light, plays an important role in describing the visual appearance of an object. Accurate and traceable determination of BTDF values is essential in fields such as satellite-based Earth remote sensing, light-shaping diffusers in optical systems, and computer graphics rendering.


This first-time EU BTDF scale comparison allows for further investigation and improvement of the European measurement capability of BTDF facilities.

Jinglin Fu
Physikalisch-Technische Bundesanstalt

Read the Original

This page is a summary of: Development of primary reference facilities and measurement comparison of standard artifacts for the bidirectional transmittance distribution function, Review of Scientific Instruments, August 2023, American Institute of Physics, DOI: 10.1063/5.0151803.
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